Yunjin Lee, Varun Muddaluru, Shiraz Anwar, Joanna Yvonne Wilson, Ana Regina Campos
The cnidarian Hydra possesses remarkable regenerative capabilities which allow it to regrow lost or damaged body parts in a matter of days. Given that many key regulators of regeneration and development are evolutionarily conserved, Hydra is a valuable model system for studying the fundamental molecular mechanisms underlying these processes. In the past, kinase inhibitors have been useful tools for determining the role of conserved signaling pathways in Hydra regeneration and patterning. Here, we present a systematic screen of a commercially available panel of kinase inhibitors for their effects on Hydra regeneration. Isolated Hydra gastric segments were exposed to 5 µM of each kinase inhibitor and regeneration of the head and foot regions were scored over a period of 96 hours. Of the 80 kinase inhibitors tested, 28 compounds resulted in abnormal regeneration. We directed our focus to the checkpoint kinase 1 (Chk1) inhibitor, SB 218078, considering the role of Chk1 in G2 checkpoint regulation and the importance of G2-paused cells in Hydra regeneration. We found that Hydra exposed to SB 218078 were unable to regenerate the head and maintain head-specific structures. Furthermore, SB 218078-treated Hydra displayed a reduction in the relative proportion of epithelial cells; however, no differences were seen for interstitial stem cells or their derivatives. Lastly, exposure to SB 218078 appeared to have no impact on the level of mitosis or apoptosis. Overall, our study demonstrates the feasibility of kinase inhibitor screens for studying Hydra regeneration processes and highlights the possible role for Hydra Chk1 in head regeneration and maintenance.
{"title":"A screen of kinase inhibitors reveals a potential role of Chk1 in regulating <i>Hydra</i> head regeneration and maintenance.","authors":"Yunjin Lee, Varun Muddaluru, Shiraz Anwar, Joanna Yvonne Wilson, Ana Regina Campos","doi":"10.1387/ijdb.210087yl","DOIUrl":"https://doi.org/10.1387/ijdb.210087yl","url":null,"abstract":"<p><p>The cnidarian <i>Hydra</i> possesses remarkable regenerative capabilities which allow it to regrow lost or damaged body parts in a matter of days. Given that many key regulators of regeneration and development are evolutionarily conserved, <i>Hydra</i> is a valuable model system for studying the fundamental molecular mechanisms underlying these processes. In the past, kinase inhibitors have been useful tools for determining the role of conserved signaling pathways in <i>Hydra</i> regeneration and patterning. Here, we present a systematic screen of a commercially available panel of kinase inhibitors for their effects on <i>Hydra</i> regeneration. Isolated <i>Hydra</i> gastric segments were exposed to 5 µM of each kinase inhibitor and regeneration of the head and foot regions were scored over a period of 96 hours. Of the 80 kinase inhibitors tested, 28 compounds resulted in abnormal regeneration. We directed our focus to the checkpoint kinase 1 (Chk1) inhibitor, SB 218078, considering the role of Chk1 in G2 checkpoint regulation and the importance of G2-paused cells in <i>Hydra</i> regeneration. We found that <i>Hydra</i> exposed to SB 218078 were unable to regenerate the head and maintain head-specific structures. Furthermore, SB 218078-treated <i>Hydra</i> displayed a reduction in the relative proportion of epithelial cells; however, no differences were seen for interstitial stem cells or their derivatives. Lastly, exposure to SB 218078 appeared to have no impact on the level of mitosis or apoptosis. Overall, our study demonstrates the feasibility of kinase inhibitor screens for studying <i>Hydra</i> regeneration processes and highlights the possible role for <i>Hydra</i> Chk1 in head regeneration and maintenance.</p>","PeriodicalId":50329,"journal":{"name":"International Journal of Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39438261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Branching morphogenesis is a crucial developmental mechanism for the formation of the typical bush-like structure of the submandibular gland (SMG). However, the detailed mechanism underlying this process remains to be fully understood. Here, we have investigated whether cross-talk may exist between the Wnt/beta-catenin signaling pathway and lama5 during the branching process in SMG development. An embryonic mouse SMG organ culture model was established, and the validity of this model was confirmed. The roles and possible interactions of the Wnt/beta-catenin signaling pathway, FGF signaling, and lama5 in the branching process were investigated by morphogenesis assays and gene expression patterns. Here, we show that the E12 or E13 SMG organ culture model can be used as an ideal approach to study the process of branching morphogenesis. Our branching morphogenesis assay revealed that the epithelial branching process can be promoted when the canonical Wnt pathway is inhibited and significantly suppressed when the wnt pathway is over activated. Further experiments indicated that FGF signaling most likely acts upstream as a negative regulator of the canonical Wnt pathway during the branching process, whose effect could be partially reversed by Wnt3a. Finally, we show that Wnt/beta-catenin signaling regulates branching morphogenesis through Lama5. We conclude that the Wnt/beta-catenin signaling pathway acting downstream of FGF signaling can serve as a negative regulatory mechanism in the process of SMG branching morphogenesis through Lama5.
{"title":"Canonical Wnt signaling regulates branching morphogenesis of submandibular gland by modulating levels of lama5.","authors":"Liming Gou, Xiaochun Ren, Ping Ji","doi":"10.1387/ijdb.200307lg","DOIUrl":"https://doi.org/10.1387/ijdb.200307lg","url":null,"abstract":"<p><p>Branching morphogenesis is a crucial developmental mechanism for the formation of the typical bush-like structure of the submandibular gland (SMG). However, the detailed mechanism underlying this process remains to be fully understood. Here, we have investigated whether cross-talk may exist between the Wnt/beta-catenin signaling pathway and lama5 during the branching process in SMG development. An embryonic mouse SMG organ culture model was established, and the validity of this model was confirmed. The roles and possible interactions of the Wnt/beta-catenin signaling pathway, FGF signaling, and lama5 in the branching process were investigated by morphogenesis assays and gene expression patterns. Here, we show that the E12 or E13 SMG organ culture model can be used as an ideal approach to study the process of branching morphogenesis. Our branching morphogenesis assay revealed that the epithelial branching process can be promoted when the canonical Wnt pathway is inhibited and significantly suppressed when the wnt pathway is over activated. Further experiments indicated that FGF signaling most likely acts upstream as a negative regulator of the canonical Wnt pathway during the branching process, whose effect could be partially reversed by Wnt3a. Finally, we show that Wnt/beta-catenin signaling regulates branching morphogenesis through Lama5. We conclude that the Wnt/beta-catenin signaling pathway acting downstream of FGF signaling can serve as a negative regulatory mechanism in the process of SMG branching morphogenesis through Lama5.</p>","PeriodicalId":50329,"journal":{"name":"International Journal of Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25409883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Crocodilians exhibit continuous tooth replacement (i.e., polyphyodonty) and have been identified as suitable models for tooth regeneration research due to the similarity in dental cavity and tooth anatomy between these creatures and humans. Various studies reporting in ovo bird embryo manipulation exist, but such reports for reptiles are virtually non-existent. Egg windowing enables direct access to oviparous vertebrate embryos and is therefore an important component of in ovo embryo manipulation experiments. The aim of the present study was to window Nile crocodile, Crocodylus niloticus eggs and assess the potential of direct manipulations, targeting the pharyngeal region where the maxilla and mandible originates. Crocodylus niloticus eggs were successfully windowed, and a limited number of individuals survived the entire gestation period. The 1st trimester of gestation was the most sensitive, and 96.78% of the mortalities occurred within this period. Our data indicate the suitable window for embryo manipulation targeting the mandibular arch and maxillary process, without a risk of damaging the chorioallantoic membrane (CAM) (which may be fatal), was between day six and eight after laying for embryos incubated at 31°C. This data will be of use for future embryo-based experiments related to jaw and tooth development in crocodiles as well as human tooth regeneration research.
{"title":"<i>In ovo</i> manipulation of Nile crocodile embryos: egg windowing and potential dental research applications.","authors":"J Christoff Truter, Jan G Myburgh","doi":"10.1387/ijdb.210196ct","DOIUrl":"https://doi.org/10.1387/ijdb.210196ct","url":null,"abstract":"<p><p>Crocodilians exhibit continuous tooth replacement (i.e., polyphyodonty) and have been identified as suitable models for tooth regeneration research due to the similarity in dental cavity and tooth anatomy between these creatures and humans. Various studies reporting <i>in ovo</i> bird embryo manipulation exist, but such reports for reptiles are virtually non-existent. Egg windowing enables direct access to oviparous vertebrate embryos and is therefore an important component of <i>in ovo</i> embryo manipulation experiments. The aim of the present study was to window Nile crocodile, <i>Crocodylus niloticus</i> eggs and assess the potential of direct manipulations, targeting the pharyngeal region where the maxilla and mandible originates. <i>Crocodylus niloticus</i> eggs were successfully windowed, and a limited number of individuals survived the entire gestation period. The 1st trimester of gestation was the most sensitive, and 96.78% of the mortalities occurred within this period. Our data indicate the suitable window for embryo manipulation targeting the mandibular arch and maxillary process, without a risk of damaging the chorioallantoic membrane (CAM) (which may be fatal), was between day six and eight after laying for embryos incubated at 31°C. This data will be of use for future embryo-based experiments related to jaw and tooth development in crocodiles as well as human tooth regeneration research.</p>","PeriodicalId":50329,"journal":{"name":"International Journal of Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39883535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rachel Collin, Caitlin M Shishido, Anabell J Cornejo, Maryna P Lesoway
Mode of development (MOD) is a key feature that influences the rate and direction of evolution of marine invertebrates. Although many groups include species with different MODs, the evolutionary loss of feeding larvae is thought to be irreversible, as the complex structures used for larval feeding and swimming are lost, reduced, or modified in many species lacking feeding larvae. This view is largely based on observations of echinoderms. Phylogenetic analysis suggests that feeding larvae have been re-gained in at least one species of calyptraeid gastropod. Further, its sister species has retained the velum, the structure used for larval feeding and swimming. Here, we document velar morphology and function in calyptraeids with 4 different MODs. Embryos of Crepidula navicella, Crepidula atrasolea, Bostrycapulus aculeatus, Bostrycapulus odites, Bostrycapulus urraca, Crepipatella dilatata, Crepipatella occulta, Crucibulum quiriquinae and Crepidula coquimbensis all hatch as crawling juveniles, yet only Crepidula coquimbensis does not make a well-formed velum during intracapsular development. The velar dimensions of 6 species with non-planktotrophic development were similar to those of planktotrophic species, while the body sizes were significantly larger. All of the species studied were able to capture and ingest particles from suspension, but several non-planktotrophic species may ingest captured particles only occasionally. Video footage suggests that some species with adelphophagic direct development capture but frequently fail to ingest particles compared to species with the other MODs. Together these lines of evidence show that, among calyptraeids at least, species that lack planktotrophic larvae often retain the structures and functions necessary to successfully capture and ingest particles, reducing the barriers to the re-evolution of planktotrophy.
{"title":"Ancestral form and function of larval feeding structures are retained during the development of non-planktotrophic gastropods.","authors":"Rachel Collin, Caitlin M Shishido, Anabell J Cornejo, Maryna P Lesoway","doi":"10.1387/ijdb.200154rc","DOIUrl":"https://doi.org/10.1387/ijdb.200154rc","url":null,"abstract":"<p><p>Mode of development (MOD) is a key feature that influences the rate and direction of evolution of marine invertebrates. Although many groups include species with different MODs, the evolutionary loss of feeding larvae is thought to be irreversible, as the complex structures used for larval feeding and swimming are lost, reduced, or modified in many species lacking feeding larvae. This view is largely based on observations of echinoderms. Phylogenetic analysis suggests that feeding larvae have been re-gained in at least one species of calyptraeid gastropod. Further, its sister species has retained the velum, the structure used for larval feeding and swimming. Here, we document velar morphology and function in calyptraeids with 4 different MODs. Embryos of <i>Crepidula navicella</i>, <i>Crepidula atrasolea</i>, <i>Bostrycapulus aculeatus</i>, <i>Bostrycapulus odites</i>, <i>Bostrycapulus urraca</i>, <i>Crepipatella dilatata</i>, <i>Crepipatella occulta</i>, <i>Crucibulum quiriquinae</i> and <i>Crepidula coquimbensis</i> all hatch as crawling juveniles, yet only <i>Crepidula coquimbensis</i> does not make a well-formed velum during intracapsular development. The velar dimensions of 6 species with non-planktotrophic development were similar to those of planktotrophic species, while the body sizes were significantly larger. All of the species studied were able to capture and ingest particles from suspension, but several non-planktotrophic species may ingest captured particles only occasionally. Video footage suggests that some species with adelphophagic direct development capture but frequently fail to ingest particles compared to species with the other MODs. Together these lines of evidence show that, among calyptraeids at least, species that lack planktotrophic larvae often retain the structures and functions necessary to successfully capture and ingest particles, reducing the barriers to the re-evolution of planktotrophy.</p>","PeriodicalId":50329,"journal":{"name":"International Journal of Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38382563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Flavio R Zolessi, Nibia Berois, M Mónica Brauer, Estela Castillo
In Uruguay, a country with a small population, and hence a small scientific community, there were no classical embryologists as such in the past. However, in the decade of the 1950s, a cumulus of favorable conditions gave rise to highly active and modern research groups in the fields of cytology and physiology, which eventually contributed to developmental biology. The advent of a long dictatorship between the 1970's and 1980's caused two things: a strong lag in local research and the migration of young investigators who learned abroad new disciplines and technologies. The coming back to democracy allowed for the return of some, now as solid researchers, and together with those who stayed, built a previously inexistent postgraduate training program and a globally-integrated academy that fostered diversity of research disciplines, including developmental biology. In this paper, we highlight the key contributions of pioneer researchers and the significant role played by academic and funding national institutions in the growth and consolidation of developmental biology in our country.
{"title":"Building the embryo of Developmental Biology in Uruguay.","authors":"Flavio R Zolessi, Nibia Berois, M Mónica Brauer, Estela Castillo","doi":"10.1387/ijdb.200141fz","DOIUrl":"https://doi.org/10.1387/ijdb.200141fz","url":null,"abstract":"<p><p>In Uruguay, a country with a small population, and hence a small scientific community, there were no classical embryologists as such in the past. However, in the decade of the 1950s, a cumulus of favorable conditions gave rise to highly active and modern research groups in the fields of cytology and physiology, which eventually contributed to developmental biology. The advent of a long dictatorship between the 1970's and 1980's caused two things: a strong lag in local research and the migration of young investigators who learned abroad new disciplines and technologies. The coming back to democracy allowed for the return of some, now as solid researchers, and together with those who stayed, built a previously inexistent postgraduate training program and a globally-integrated academy that fostered diversity of research disciplines, including developmental biology. In this paper, we highlight the key contributions of pioneer researchers and the significant role played by academic and funding national institutions in the growth and consolidation of developmental biology in our country.</p>","PeriodicalId":50329,"journal":{"name":"International Journal of Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1387/ijdb.200141fz","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38380167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Roberto Mayor is a prominent Chilean developmental biologist working in the UK and an advocate of the developmental biology discipline in Latin America. Roberto started as a preimplantation mouse developmental biologist during his undergraduate and graduate studies in Chile. Yet, he now uses Xenopus and zebrafish to elucidate the mechanisms that drive the directed collective locomotion of neural crest cells. What life events moulded the research career of Roberto across the years? This article addresses this question and provides a personal perspective on his scientific achievements. The story of Roberto is a mix of turns and cycles that ultimately guided him to the migrating neural crest. Turns that made him shift between model organisms and scientific topics. Cycles that drove him back and forth between Chile and the UK and which have connected his early studies as an undergraduate student with the most recent work of his lab. A big lesson that we can learn from the life of Roberto is that no matter how much you plan your life always serendipity plays a significant role. But you have to be alert and brave to take the opportunities that life offers you.
{"title":"A tale of turns and cycles guiding to neural crest migration - an interview with Roberto Mayor.","authors":"Miguel L Concha","doi":"10.1387/ijdb.200026mc","DOIUrl":"https://doi.org/10.1387/ijdb.200026mc","url":null,"abstract":"<p><p>Roberto Mayor is a prominent Chilean developmental biologist working in the UK and an advocate of the developmental biology discipline in Latin America. Roberto started as a preimplantation mouse developmental biologist during his undergraduate and graduate studies in Chile. Yet, he now uses <i>Xenopus</i> and zebrafish to elucidate the mechanisms that drive the directed collective locomotion of neural crest cells. What life events moulded the research career of Roberto across the years? This article addresses this question and provides a personal perspective on his scientific achievements. The story of Roberto is a mix of turns and cycles that ultimately guided him to the migrating neural crest. Turns that made him shift between model organisms and scientific topics. Cycles that drove him back and forth between Chile and the UK and which have connected his early studies as an undergraduate student with the most recent work of his lab. A big lesson that we can learn from the life of Roberto is that no matter how much you plan your life always serendipity plays a significant role. But you have to be alert and brave to take the opportunities that life offers you.</p>","PeriodicalId":50329,"journal":{"name":"International Journal of Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38380172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jorge E. Allende is a biochemist trained in the United States of America who has been a professor at the University of Chile since 1961. He has served in many leadership positions in both Chilean and international scientific organizations and academic institutions. He led the International Cell Research Organization, the Latin American Network of Biological Sciences and obtained the Chilean National Science Prize. He belongs to the Chilean Academy of Sciences and is a foreign member of the National Academy of Sciences (USA) and also of the National Academy of Medicine (USA). During his career, besides leading a highly successful research group, he was instrumental in generating an esprit de corps among Latin American scientists of all fields in biology starting in the late 1960's. He began a longstanding tradition by organizing advanced training courses for young scientists from the region who would not have otherwise had the opportunity to experience the latest methods and concepts in biological research, courses that had world leading researchers as instructors. A constant focus of his efforts consisted in promoting the establishment of postgraduate programs in biology throughout the continent, coordinating international funding programs aimed at scientific development in the third world and, more recently, advocating for science education among children and school teachers as the only way to achieve scientific literacy in our societies. In this interview, we explore how these issues were addressed by him and his counterparts in other Latin American countries, at a time when they had to start, essentially, from scratch.
Jorge E. Allende是一位在美国接受培训的生物化学家,自1961年以来一直是智利大学的教授。他曾在智利和国际科学组织和学术机构担任过许多领导职务。他领导了国际细胞研究组织、拉丁美洲生物科学网络,并获得了智利国家科学奖。他是智利科学院院士,也是美国国家科学院和美国国家医学院的外籍院士。在他的职业生涯中,除了领导一个非常成功的研究小组外,他还在20世纪60年代末开始在拉丁美洲所有生物学领域的科学家中培养了团队精神。他开创了一个长期以来的传统,为来自该地区的年轻科学家组织高级培训课程,否则他们将没有机会体验生物研究的最新方法和概念,这些课程有世界领先的研究人员担任讲师。他一直致力于促进整个欧洲大陆生物学研究生课程的建立,协调旨在第三世界科学发展的国际资助项目,最近,他倡导在儿童和学校教师中进行科学教育,这是在我们的社会中实现科学素养的唯一途径。在这次采访中,我们探讨了他和其他拉丁美洲国家的同行是如何解决这些问题的,当时他们不得不从头开始,基本上是从零开始。
{"title":"Six decades of scientific pan-Americanism - an interview with Jorge E. Allende.","authors":"Miguel L Allende","doi":"10.1387/ijdb.200050ma","DOIUrl":"https://doi.org/10.1387/ijdb.200050ma","url":null,"abstract":"<p><p>Jorge E. Allende is a biochemist trained in the United States of America who has been a professor at the University of Chile since 1961. He has served in many leadership positions in both Chilean and international scientific organizations and academic institutions. He led the International Cell Research Organization, the Latin American Network of Biological Sciences and obtained the Chilean National Science Prize. He belongs to the Chilean Academy of Sciences and is a foreign member of the National Academy of Sciences (USA) and also of the National Academy of Medicine (USA). During his career, besides leading a highly successful research group, he was instrumental in generating an <i>esprit de corps</i> among Latin American scientists of all fields in biology starting in the late 1960's. He began a longstanding tradition by organizing advanced training courses for young scientists from the region who would not have otherwise had the opportunity to experience the latest methods and concepts in biological research, courses that had world leading researchers as instructors. A constant focus of his efforts consisted in promoting the establishment of postgraduate programs in biology throughout the continent, coordinating international funding programs aimed at scientific development in the third world and, more recently, advocating for science education among children and school teachers as the only way to achieve scientific literacy in our societies. In this interview, we explore how these issues were addressed by him and his counterparts in other Latin American countries, at a time when they had to start, essentially, from scratch.</p>","PeriodicalId":50329,"journal":{"name":"International Journal of Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38380585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jorge Torres-Paz, Eugene M Tine, Kathleen E Whitlock
The olfactory epithelia arise from morphologically identifiable structures called olfactory placodes. Sensory placodes are generally described as being induced from the ectoderm suggesting that their development is separate from the coordinated cell movements generating the central nervous system. Previously, we have shown that the olfactory placodes arise from a large field of cells bordering the telencephalic precursors in the neural plate, and that cell movements, not cell division, underlie olfactory placode morphogenesis. Subsequently by image analysis, cells were tracked as they moved in the continuous sheet of neurectoderm giving rise to the peripheral (olfactory organs) and central (olfactory bulbs) nervous system (Torres-Paz and Whitlock, 2014). These studies lead to a model whereby the olfactory epithelia develop from within the border of the neural late and are a neural tube derivative, similar to the retina of the eye (Torres-Paz and Whitlock, 2014; Whitlock, 2008). Here we show that randomly generated clones of cells extend across the morphologically differentiated olfactory placodes/olfactory bulbs, and test the hypothesis that these structures are patterned by a different level of distal-less (dlx) gene expression subdividing the anterior neurectoderm into OP precursors (high Dlx expression) and OB precursors (lower Dlx expression). Manipulation of DLX protein and RNA levels resulted in morphological changes in the size of the olfactory epithelia and olfactory bulb. Thus, the olfactory epithelia and bulbs arise from a common neurectodermal region and develop in concert through coordinated morphological movements.
嗅觉上皮由形态可识别的嗅觉基板结构产生。感觉基板通常被描述为由外胚层诱导产生,这表明它们的发育与产生中枢神经系统的协调细胞运动是分开的。先前,我们已经证明嗅觉基板产生于与神经板中端脑前体相邻的大范围细胞,并且细胞运动,而不是细胞分裂,是嗅觉基板形态发生的基础。随后,通过图像分析,跟踪细胞在神经胚层连续片中产生外周(嗅觉器官)和中枢(嗅球)神经系统的运动过程(Torres-Paz和Whitlock, 2014)。这些研究得出了一种模型,即嗅觉上皮从神经末梢的边界内发育而来,是神经管的衍生物,类似于眼睛的视网膜(Torres-Paz and Whitlock, 2014;怀特洛克,2008)。在这里,我们展示了随机生成的细胞克隆跨越形态分化的嗅基板/嗅球,并验证了这些结构是由不同水平的远端无(dlx)基因表达形成的假设,这些基因表达将前神经胚层细分为OP前体(高dlx表达)和OB前体(低dlx表达)。DLX蛋白和RNA水平的改变导致嗅上皮和嗅球大小的形态学改变。因此,嗅上皮和嗅球起源于一个共同的神经胚层区域,并通过协调的形态运动协调发展。
{"title":"Dissecting the neural divide: a continuous neurectoderm gives rise to the olfactory placode and bulb.","authors":"Jorge Torres-Paz, Eugene M Tine, Kathleen E Whitlock","doi":"10.1387/ijdb.200097kw","DOIUrl":"https://doi.org/10.1387/ijdb.200097kw","url":null,"abstract":"<p><p>The olfactory epithelia arise from morphologically identifiable structures called olfactory placodes. Sensory placodes are generally described as being induced from the ectoderm suggesting that their development is separate from the coordinated cell movements generating the central nervous system. Previously, we have shown that the olfactory placodes arise from a large field of cells bordering the telencephalic precursors in the neural plate, and that cell movements, not cell division, underlie olfactory placode morphogenesis. Subsequently by image analysis, cells were tracked as they moved in the continuous sheet of neurectoderm giving rise to the peripheral (olfactory organs) and central (olfactory bulbs) nervous system (Torres-Paz and Whitlock, 2014). These studies lead to a model whereby the olfactory epithelia develop from within the border of the neural late and are a neural tube derivative, similar to the retina of the eye (Torres-Paz and Whitlock, 2014; Whitlock, 2008). Here we show that randomly generated clones of cells extend across the morphologically differentiated olfactory placodes/olfactory bulbs, and test the hypothesis that these structures are patterned by a different level of distal-less (dlx) gene expression subdividing the anterior neurectoderm into OP precursors (high Dlx expression) and OB precursors (lower Dlx expression). Manipulation of DLX protein and RNA levels resulted in morphological changes in the size of the olfactory epithelia and olfactory bulb. Thus, the olfactory epithelia and bulbs arise from a common neurectodermal region and develop in concert through coordinated morphological movements.</p>","PeriodicalId":50329,"journal":{"name":"International Journal of Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38382573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Salamanders are the only vertebrates that can regenerate limbs as adults. This makes them ideal models to investigate the cellular and molecular mechanisms of tissue regeneration. Ambystoma mexicanum and Nothopthalmus viridescens have long served as primary salamander models of limb regeneration, and the recent sequencing of the axolotl genome now provides a blueprint to mine regeneration insights from other salamander species. In particular, there is a need to study South American plethodontid salamanders that present different patterns of limb development and regeneration. A broader sampling of species using next-generation sequencing approaches is needed to reveal shared and unique mechanisms of regeneration, and more generally, the evolutionary history of salamander limb regeneration.
{"title":"Limb regeneration in salamanders: the plethodontid tale.","authors":"Claudia M Arenas-Gómez, Jean-Paul Delgado","doi":"10.1387/ijdb.200228jd","DOIUrl":"https://doi.org/10.1387/ijdb.200228jd","url":null,"abstract":"<p><p>Salamanders are the only vertebrates that can regenerate limbs as adults. This makes them ideal models to investigate the cellular and molecular mechanisms of tissue regeneration. <i>Ambystoma mexicanum</i> and <i>Nothopthalmus viridescens</i> have long served as primary salamander models of limb regeneration, and the recent sequencing of the axolotl genome now provides a blueprint to mine regeneration insights from other salamander species. In particular, there is a need to study South American plethodontid salamanders that present different patterns of limb development and regeneration. A broader sampling of species using next-generation sequencing approaches is needed to reveal shared and unique mechanisms of regeneration, and more generally, the evolutionary history of salamander limb regeneration.</p>","PeriodicalId":50329,"journal":{"name":"International Journal of Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1387/ijdb.200228jd","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38477966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The axial skeleton of the anurans has undergone an evolutionary reduction of its bone elements. This structural plan is strongly preserved throughout the order and would have emerged as a highly specialized anatomical adaptation to its locomotor jumping pattern. The development programs that direct the vertebral morphogenesis of the anurans are poorly described and the molecular bases that have caused their pattern to differ from other tetrapods are completely unknown. In this work, we review the ontogeny of the spinal column of the anurans and explore the genetic mechanisms that could explain the morphological difference and the maintenance of the body plan during evolution. Here, we propose that the absence of caudal osseous elements, as a consequence of the inability of sclerotomes to form cartilaginous condensations in frogs, could be due to changes in both pattern and expression levels of Hox, Pax1, Pax9 and Uncx4.1 genes along the anteroposterior axis. The anteriorised expression of the Hox genes together with the reduction in the expression levels of Pax1, Pax9 and Uncx4 in the posterior somites could explain, at least partly, the loss of caudal vertebrae in the anurans during evolution.
{"title":"Delineating the anuran axial skeleton.","authors":"Sara S Sánchez, Romel S Sánchez","doi":"10.1387/ijdb.200230ss","DOIUrl":"https://doi.org/10.1387/ijdb.200230ss","url":null,"abstract":"<p><p>The axial skeleton of the <i>anurans</i> has undergone an evolutionary reduction of its bone elements. This structural plan is strongly preserved throughout the order and would have emerged as a highly specialized anatomical adaptation to its locomotor jumping pattern. The development programs that direct the vertebral morphogenesis of the anurans are poorly described and the molecular bases that have caused their pattern to differ from other tetrapods are completely unknown. In this work, we review the ontogeny of the spinal column of the anurans and explore the genetic mechanisms that could explain the morphological difference and the maintenance of the body plan during evolution. Here, we propose that the absence of caudal osseous elements, as a consequence of the inability of sclerotomes to form cartilaginous condensations in frogs, could be due to changes in both pattern and expression levels of <i>Hox</i>, <i>Pax1</i>, <i>Pax9</i> and <i>Uncx4.1</i> genes along the anteroposterior axis. The anteriorised expression of the <i>Hox</i> genes together with the reduction in the expression levels of <i>Pax1</i>, <i>Pax9</i> and <i>Uncx4</i> in the posterior somites could explain, at least partly, the loss of caudal vertebrae in the anurans during evolution.</p>","PeriodicalId":50329,"journal":{"name":"International Journal of Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38477968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}