Lola Moreano-Arrobo, Oscar D Pérez, Federico D Brown, Fernanda X Oyarzún, Cristian B Canales-Aguirre
Elysia diomedea, otherwise known as the "Mexican dancer", aries in adult size and color across its geographical distribution in Ecuador. Because of morphological variation and the absence of genetic information for this species in Ecuador, we analyzed mtDNA sequences in three populations (Ballenita, La Cabuya, and Mompiche) and confirmed that individuals from the three locations belonged to E. diomedea and that there was no population structure that could explain their morphological differences. Next, we analyzed general aspects about the reproductive biology and embryology of this species. Live slugs from the Ballenita population were maintained and reproduced ex situ. Egg ribbons and embryos were fixed and observed by brightfield and confocal microscopy. We observed a single embryo per capsule, 98 embryos per mm2 of egg ribbon, and compared the cleavage pattern of this species to that of other heterobranchs and spiralians. E. diomedea early development was characterized by a slight unequal first cleavage, occurrence of a 3-cell stage in the second cleavage, and the formation of an enlarged second quartet of micromeres. We observed clear yolk bodies in the egg capsules of some eggs ribbons at early stages of development. Both reproductive and embryological characteristics, such as presence of stomodeum in the larva, and ingestion of particles after hatching confirmed the planktotrophic veliger larvae of this species, consistent with the majority of sacoglossans from the Eastern and Northeast Pacific Oceans.
{"title":"The \"Mexican dancer\" in Ecuador: molecular confirmation, embryology and planktotrophy in the sea slug <i>Elysia diomedea</i>.","authors":"Lola Moreano-Arrobo, Oscar D Pérez, Federico D Brown, Fernanda X Oyarzún, Cristian B Canales-Aguirre","doi":"10.1387/ijdb.200157fo","DOIUrl":"https://doi.org/10.1387/ijdb.200157fo","url":null,"abstract":"<p><p><i>Elysia diomedea</i>, otherwise known as the \"Mexican dancer\", aries in adult size and color across its geographical distribution in Ecuador. Because of morphological variation and the absence of genetic information for this species in Ecuador, we analyzed mtDNA sequences in three populations (Ballenita, La Cabuya, and Mompiche) and confirmed that individuals from the three locations belonged to <i>E. diomedea</i> and that there was no population structure that could explain their morphological differences. Next, we analyzed general aspects about the reproductive biology and embryology of this species. Live slugs from the Ballenita population were maintained and reproduced <i>ex situ</i>. Egg ribbons and embryos were fixed and observed by brightfield and confocal microscopy. We observed a single embryo per capsule, 98 embryos per mm<sup>2</sup> of egg ribbon, and compared the cleavage pattern of this species to that of other heterobranchs and spiralians. <i>E. diomedea</i> early development was characterized by a slight unequal first cleavage, occurrence of a 3-cell stage in the second cleavage, and the formation of an enlarged second quartet of micromeres. We observed clear yolk bodies in the egg capsules of some eggs ribbons at early stages of development. Both reproductive and embryological characteristics, such as presence of stomodeum in the larva, and ingestion of particles after hatching confirmed the planktotrophic veliger larvae of this species, consistent with the majority of sacoglossans from the Eastern and Northeast Pacific Oceans.</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.200157fo","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38382564","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}
This issue of the International Journal of Developmental Biology is dedicated to Ibero-America, and includes research articles from Argentina, Brazil, Chile, Colombia, Ecuador, Mexico, Panama, Puerto Rico, and Uruguay. It also describes the history of developmental biology in several Ibero-American countries. Moreover, the volume contains interviews with scientists living in the region and abroad. Other articles highlight The Latin American Society for Developmental Biology (LASDB), and the International Courses. The main purpose of this volume is to stimulate interest and reseach in developmental biology in Ibero-America.
{"title":"A display of Developmental Biology in Ibero-America.","authors":"Eugenia M Del Pino","doi":"10.1387/ijdb.200104ed","DOIUrl":"https://doi.org/10.1387/ijdb.200104ed","url":null,"abstract":"<p><p>This issue of the International Journal of Developmental Biology is dedicated to Ibero-America, and includes research articles from Argentina, Brazil, Chile, Colombia, Ecuador, Mexico, Panama, Puerto Rico, and Uruguay. It also describes the history of developmental biology in several Ibero-American countries. Moreover, the volume contains interviews with scientists living in the region and abroad. Other articles highlight The Latin American Society for Developmental Biology (LASDB), and the International Courses. The main purpose of this volume is to stimulate interest and reseach in developmental biology in Ibero-America.</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":"38380161","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}
Andrea M J Weiner, Gabriela Coux, Pablo Armas, Nora Calcaterra
Although the vertebrate head has evolved to a wide collection of adaptive shapes, the fundamental signalling pathways and cellular events that outline the head skeleton have proven to be highly conserved. This conservation suggests that major morphological differences are due to changes in differentiation and morphogenetic programs downstream of a well-maintained developmental prepattern. Here we provide a brief examination of the mechanisms and pathways responsible for vertebrate head development, as well as an overview of the animal models suitable for studying face development. In addition, we describe the criteria for neurocristopathy classification, highlighting the contribution of zebrafish to the modelling of Treacher Collins/Franceschetti Syndrome, an emblematic neurocristopathy. The contributions from our laboratory reveal that proper zebrafish head development depends on the fine-tuning of developmental-gene expression mediated by nucleic acid binding proteins able to regulate DNA conformation and / or the neuroepithelium redox state.
{"title":"Insights into vertebrate head development: from cranial neural crest to the modelling of neurocristopathies.","authors":"Andrea M J Weiner, Gabriela Coux, Pablo Armas, Nora Calcaterra","doi":"10.1387/ijdb.200229nc","DOIUrl":"https://doi.org/10.1387/ijdb.200229nc","url":null,"abstract":"<p><p>Although the vertebrate head has evolved to a wide collection of adaptive shapes, the fundamental signalling pathways and cellular events that outline the head skeleton have proven to be highly conserved. This conservation suggests that major morphological differences are due to changes in differentiation and morphogenetic programs downstream of a well-maintained developmental prepattern. Here we provide a brief examination of the mechanisms and pathways responsible for vertebrate head development, as well as an overview of the animal models suitable for studying face development. In addition, we describe the criteria for neurocristopathy classification, highlighting the contribution of zebrafish to the modelling of Treacher Collins/Franceschetti Syndrome, an emblematic neurocristopathy. The contributions from our laboratory reveal that proper zebrafish head development depends on the fine-tuning of developmental-gene expression mediated by nucleic acid binding proteins able to regulate DNA conformation and / or the neuroepithelium redox state.</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.200229nc","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38477967","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}
Shaghayegh Hasanpour, Soheil Eagderi, Hadi Poorbagher, Mohammad Hasanpour
To investigate the role of maternal Activin-like factors in the preservation of stemness and mesendoderm induction, their effects were promoted and inhibited using synthetic human Activin A or SB-505124 treatments, respectively, before the maternal to zygotic transition (MZT). To study the role of zygotic Activin-like factors, SB-505124 treatment was also used after the MZT. Promoting the signaling intensity of maternal Activin-like factors led to premature differentiation, loss of stemness, and no mesendoderm malformation, while its alleviation delayed the differentiation and caused various malformations. Inhibition of the zygotic Activin-like factors was associated with suppressing the ndr1, ndr2, oct4 (pou5f3), mycb and notail transcription as well as differentiation retardation at the oblong stage, and a broad spectrum of anomalies in a dose-dependent manner. Together, promoting the signal intensity of maternal Activin-like factors drove development along with mesendodermal differentiation, while suppression of the maternal or zygotic ones maintained the pluripotent state and delayed differentiation.
{"title":"Maternal and zygotic activin signaling promotes adequate pattern and differentiation of mesoderm through regulation of pluripotency genes during zebrafish development.","authors":"Shaghayegh Hasanpour, Soheil Eagderi, Hadi Poorbagher, Mohammad Hasanpour","doi":"10.1387/ijdb.210073se","DOIUrl":"https://doi.org/10.1387/ijdb.210073se","url":null,"abstract":"<p><p>To investigate the role of maternal Activin-like factors in the preservation of stemness and mesendoderm induction, their effects were promoted and inhibited using synthetic human Activin A or SB-505124 treatments, respectively, before the maternal to zygotic transition (MZT). To study the role of zygotic Activin-like factors, SB-505124 treatment was also used after the MZT. Promoting the signaling intensity of maternal Activin-like factors led to premature differentiation, loss of stemness, and no mesendoderm malformation, while its alleviation delayed the differentiation and caused various malformations. Inhibition of the zygotic Activin-like factors was associated with suppressing the <i>ndr1</i>, <i>ndr2</i>, <i>oct4</i> (<i>pou5f3</i>), <i>mycb</i> and <i>notail</i> transcription as well as differentiation retardation at the oblong stage, and a broad spectrum of anomalies in a dose-dependent manner. Together, promoting the signal intensity of maternal Activin-like factors drove development along with mesendodermal differentiation, while suppression of the maternal or zygotic ones maintained the pluripotent state and delayed differentiation.</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":"39438259","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}
Sana Fatma, Ravindra Kumar, Anshuman Dixit, Rajeeb K Swain
The lateral line system is a mechanosensory organ of fish and amphibians that detects changes in water flow and is formed by the coordinated action of many signalling pathways. These signalling pathways can easily be targeted in zebrafish using pharmacological inhibitors to decipher their role in lateral line system development at cellular and molecular level. We have identified two uncharacterized proteins, whose mRNA are expressed in the lateral line system of zebrafish. One of these proteins, uncharacterized protein LOC564095 precursor, is conserved across vertebrates and its mRNA is expressed in posterior lateral line primordium (pLLP). The other uncharacterized protein, LOC100536887, is present only in the teleost fishes and its mRNA is expressed in neuromasts. We show that inhibition of retinoic acid (RA) signalling reduces the expression of both of these uncharacterized genes. It is reported that inhibition of RA signalling during gastrulation starting at 7 hours post fertilization (hpf) abrogates pLLP formation, and inhibition of RA signalling at 10 hpf delays the initiation of pLLP migration. Here, we show that inhibition of RA signalling before and during segmentation (9-16 hpf) results in delayed initiation and reduced speed of pLLP migration, as well as inhibition of posterior neuromasts formation.
{"title":"Expression of two uncharacterized protein coding genes in zebrafish lateral line system.","authors":"Sana Fatma, Ravindra Kumar, Anshuman Dixit, Rajeeb K Swain","doi":"10.1387/ijdb.210066rs","DOIUrl":"https://doi.org/10.1387/ijdb.210066rs","url":null,"abstract":"<p><p>The lateral line system is a mechanosensory organ of fish and amphibians that detects changes in water flow and is formed by the coordinated action of many signalling pathways. These signalling pathways can easily be targeted in zebrafish using pharmacological inhibitors to decipher their role in lateral line system development at cellular and molecular level. We have identified two uncharacterized proteins, whose mRNA are expressed in the lateral line system of zebrafish. One of these proteins, uncharacterized protein LOC564095 precursor, is conserved across vertebrates and its mRNA is expressed in posterior lateral line primordium (pLLP). The other uncharacterized protein, LOC100536887, is present only in the teleost fishes and its mRNA is expressed in neuromasts. We show that inhibition of retinoic acid (RA) signalling reduces the expression of both of these uncharacterized genes. It is reported that inhibition of RA signalling during gastrulation starting at 7 hours post fertilization (hpf) abrogates pLLP formation, and inhibition of RA signalling at 10 hpf delays the initiation of pLLP migration. Here, we show that inhibition of RA signalling before and during segmentation (9-16 hpf) results in delayed initiation and reduced speed of pLLP migration, as well as inhibition of posterior neuromasts formation.</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":"39706104","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}
Valentina Garcia-Lee, Martha E Díaz-Hernandez, Jesús Chimal-Monroy
The cell differentiation of the musculoskeletal system is highly coordinated during limb development. In the distal-most region of the limb, WNT and FGF released from the apical ectodermal ridge maintain mesenchymal cells in the undifferentiated stage. Once the cells stop receiving WNT and FGF, they respond to differentiation signals. Particularly during tendon development, mesenchymal cells enter the cell differentiation program once Scleraxis (Scx) gene expression occurs. Among the signals that trigger the cell differentiation programs, TGFβ signaling has been found to be closely involved in tendon differentiation. However, whether Scx gene expression depends merely on TGFβ signaling or other signals is still not fully understood. In the present study, considering that WNT/β-catenin is an inhibitory signal of cell differentiation, we speculated possible antagonistic or additive effects between canonical Wnt/β-catenin and TGFβ/SMAD signaling pathways to control Scx gene expression. We found that the blockade of WNT/β-catenin promoted Scx gene expression. In contrast, the inhibition of TGFβ/SMAD signaling did not maintain Scx gene expression. Interestingly, the blockade of both WNT/β-catenin and TGFβ/SMAD signaling at the same time promoted Scx gene expression. Thus the inhibition of WNT/β-catenin signaling appears to be necessary and sufficient to induce Scx gene expression.
{"title":"Inhibition of WNT/β-catenin is necessary and sufficient to induce <i>Scx</i> expression in developing tendons of chicken limb.","authors":"Valentina Garcia-Lee, Martha E Díaz-Hernandez, Jesús Chimal-Monroy","doi":"10.1387/ijdb.200166jc","DOIUrl":"https://doi.org/10.1387/ijdb.200166jc","url":null,"abstract":"<p><p>The cell differentiation of the musculoskeletal system is highly coordinated during limb development. In the distal-most region of the limb, WNT and FGF released from the apical ectodermal ridge maintain mesenchymal cells in the undifferentiated stage. Once the cells stop receiving WNT and FGF, they respond to differentiation signals. Particularly during tendon development, mesenchymal cells enter the cell differentiation program once <i>Scleraxis</i> (<i>Scx</i>) gene expression occurs. Among the signals that trigger the cell differentiation programs, TGFβ signaling has been found to be closely involved in tendon differentiation. However, whether <i>Scx</i> gene expression depends merely on TGFβ signaling or other signals is still not fully understood. In the present study, considering that WNT/β-catenin is an inhibitory signal of cell differentiation, we speculated possible antagonistic or additive effects between canonical Wnt/β-catenin and TGFβ/SMAD signaling pathways to control <i>Scx</i> gene expression. We found that the blockade of WNT/β-catenin promoted <i>Scx</i> gene expression. In contrast, the inhibition of TGFβ/SMAD signaling did not maintain <i>Scx</i> gene expression. Interestingly, the blockade of both WNT/β-catenin and TGFβ/SMAD signaling at the same time promoted <i>Scx</i> gene expression. Thus the inhibition of WNT/β-catenin signaling appears to be necessary and sufficient to induce <i>Scx</i> gene expression.</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.200166jc","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38382566","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}
María José Salazar-Nicholls, Francisca Hervas, Sofía I Muñoz-Tobar, Ana-Belén Carrillo, Heisel Ricaurte, Santiago R Ron, Andrés Romero-Carvajal
The adaptive role of amphibian oocyte melanic pigmentation and its molecular control are still elusive. Here we present evidence of a polymorphism in egg pigmentation in the emerald glass frog Espadarana prosoblepon. In Ecuadorian natural populations of this species, females can lay dark brown or pale eggs that develop into normal pigmented tadpoles and adults. This trait is a sex-limited phenotype which is inherited like a recessive allele that we called pale eggs like (pel). The pel phenotype is exclusive of oocyte cortical melanic pigmentation, which is reduced in comparison to wild type (wt) dark pigmented oocytes. Consequently, pel early embryos are paler in appearance, with reduced melanic pigmentation distributed to early blastomeres and embryonic ectoderm. However, these embryos form normal melanocyte derived pigmentation. Finally, we discuss the origin of this polymorphism and propose the use of E. prosoblepon as a model to study the adaptive role of egg pigmentation.
{"title":"A polymorphism in oocyte pigmentation in natural populations of the glass frog <i>Espadarana prosoblepon</i> (Centrolenidae).","authors":"María José Salazar-Nicholls, Francisca Hervas, Sofía I Muñoz-Tobar, Ana-Belén Carrillo, Heisel Ricaurte, Santiago R Ron, Andrés Romero-Carvajal","doi":"10.1387/ijdb.200074ar","DOIUrl":"https://doi.org/10.1387/ijdb.200074ar","url":null,"abstract":"<p><p>The adaptive role of amphibian oocyte melanic pigmentation and its molecular control are still elusive. Here we present evidence of a polymorphism in egg pigmentation in the emerald glass frog <i>Espadarana prosoblepon</i>. In Ecuadorian natural populations of this species, females can lay dark brown or pale eggs that develop into normal pigmented tadpoles and adults. This trait is a sex-limited phenotype which is inherited like a recessive allele that we called <i>pale eggs like (pel)</i>. The <i>pel</i> phenotype is exclusive of oocyte cortical melanic pigmentation, which is reduced in comparison to wild type <i>(wt)</i> dark pigmented oocytes. Consequently, <i>pel</i> early embryos are paler in appearance, with reduced melanic pigmentation distributed to early blastomeres and embryonic ectoderm. However, these embryos form normal melanocyte derived pigmentation. Finally, we discuss the origin of this polymorphism and propose the use of <i>E. prosoblepon</i> as a model to study the adaptive role of egg pigmentation.</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.200074ar","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38382570","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}
Luis Covarrubias, José-Ángel Martínez-Sarmiento, Concepción Valencia, Andras Nagy, David Hernández-García
The amount of proteins of the regulatory pluripotency network can be determinant for somatic cell reprogramming into induced pluripotent stem cells (iPSCs) as well as for the maintenance of pluripotent stem cells (PSCs). Here, we report a transposon-based reprogramming system (PB-Booster) that allowed high expression levels of a polycistronic transgene containing Myc, Klf4, Oct4 and Sox2 (MKOS) and showed increased reprogramming efficiency of fresh mouse embryonic fibroblasts (MEFs) into iPSCs under low, but not under high, MKOS expression levels. In contrast, MEFs after 2 passages derived into a similar number of iPSC colonies as fresh MEFs at a high MKOS dose, but this number was reduced at a low MKOS dose. Timing of reprogramming was not affected by MKOS expression levels but, importantly, exogenous MKOS expression in established PSCs caused a significant cell loss. At high but not at low MKOS expression levels, MEFs of the CD1 strain produced more initial cell clusters than iPSCs and, although reprogrammed at a similar efficiency as MEFs of the 129/Sv strain, iPSCs could not be maintained in the absence of exogenous MKOS. In CD1-iPSCs, Oct4, Nanog, Rex1 and Esrrb expression levels were reduced when compared with the levels in PSCs derived from the 129/Sv strain. Culture of CD1-iPSCs in medium with MEK and GSK3β inhibitors allowed their self-renewal in the absence of exogenous MKOS, but the expression levels of Oct4, Nanog, Rex1 and Esrrb were only partially increased. Despite the reduced levels of those pluripotency factors, CD1-iPSC kept high capacity for contribution to chimeric mouse embryos. Therefore, levels of regulatory pluripotency factors influence reprogramming initiation and PSC maintenance in vitro without affecting their differentiation potential in vivo.
{"title":"The levels of reprogramming factors influence the induction and maintenance of pluripotency: the case of CD1 mouse strain cells.","authors":"Luis Covarrubias, José-Ángel Martínez-Sarmiento, Concepción Valencia, Andras Nagy, David Hernández-García","doi":"10.1387/ijdb.200233lc","DOIUrl":"https://doi.org/10.1387/ijdb.200233lc","url":null,"abstract":"<p><p>The amount of proteins of the regulatory pluripotency network can be determinant for somatic cell reprogramming into induced pluripotent stem cells (iPSCs) as well as for the maintenance of pluripotent stem cells (PSCs). Here, we report a transposon-based reprogramming system (PB-Booster) that allowed high expression levels of a polycistronic transgene containing <i>Myc,</i> K<i>lf4,</i> O<i>ct4</i> and <i>Sox2</i> (<i>MKOS</i>) and showed increased reprogramming efficiency of fresh mouse embryonic fibroblasts (MEFs) into iPSCs under low, but not under high, <i>MKOS</i> expression levels. In contrast, MEFs after 2 passages derived into a similar number of iPSC colonies as fresh MEFs at a high MKOS dose, but this number was reduced at a low MKOS dose. Timing of reprogramming was not affected by <i>MKOS</i> expression levels but, importantly, exogenous <i>MKOS</i> expression in established PSCs caused a significant cell loss. At high but not at low <i>MKOS</i> expression levels, MEFs of the CD1 strain produced more initial cell clusters than iPSCs and, although reprogrammed at a similar efficiency as MEFs of the 129/Sv strain, iPSCs could not be maintained in the absence of exogenous <i>MKOS</i>. In CD1-iPSCs, <i>Oct4</i>, <i>Nanog</i>, <i>Rex1</i> and <i>Esrrb</i> expression levels were reduced when compared with the levels in PSCs derived from the 129/Sv strain. Culture of CD1-iPSCs in medium with MEK and GSK3β inhibitors allowed their self-renewal in the absence of exogenous <i>MKOS</i>, but the expression levels of <i>Oct4</i>, <i>Nanog</i>, <i>Rex1</i> and <i>Esrrb</i> were only partially increased. Despite the reduced levels of those pluripotency factors, CD1-iPSC kept high capacity for contribution to chimeric mouse embryos. Therefore, levels of regulatory pluripotency factors influence reprogramming initiation and PSC maintenance <i>in vitro</i> without affecting their differentiation potential <i>in vivo</i>.</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.200233lc","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38380170","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}
Development without a free-living tadpole is common among Ibero American frogs. The most derived condition is direct development where the tadpole has been eliminated, and the most investigated direct developing frog is Eleutherodactylus coqui. To provide a different point-of-view, an imaginary interview with a coqui is conducted. Opinions are offered on invasive species, developmental features that are surprisingly conserved, and novelty in germ layer specification.
{"title":"Development of a non-amphibious amphibian - an interview with a coquí.","authors":"Richard P Elinson","doi":"10.1387/ijdb.190386re","DOIUrl":"https://doi.org/10.1387/ijdb.190386re","url":null,"abstract":"<p><p>Development without a free-living tadpole is common among Ibero American frogs. The most derived condition is direct development where the tadpole has been eliminated, and the most investigated direct developing frog is <i>Eleutherodactylus coqui</i>. To provide a different point-of-view, an imaginary interview with a coqui is conducted. Opinions are offered on invasive species, developmental features that are surprisingly conserved, and novelty in germ layer specification.</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":"38380587","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}
David Quispe-Parra, Griselle Valentín, José E García-Arrarás
Regeneration of lost or injured organs is an intriguing process in which numerous cellular events take place to form the new structure. Studies of this process during reconstitution of the intestine have been performed in echinoderms, particularly in holothurians. Many cellular events triggered during regeneration have been described using the sea cucumber Holothuria glaberrima as a research model. More recent experiments have targeted the molecular mechanisms behind the process, a task that has been facilitated by the new sequencing technologies now available. In this review, we present studies involving cellular processes and the genes that have been identified to be associated with the early events of gut regeneration. We also present ongoing efforts to perform functional studies necessary to establish the role(s) of the identified genes. A synopsis of the studies is given with the course of the regenerative process established so far.
{"title":"A roadmap for intestinal regeneration.","authors":"David Quispe-Parra, Griselle Valentín, José E García-Arrarás","doi":"10.1387/ijdb.200227dq","DOIUrl":"https://doi.org/10.1387/ijdb.200227dq","url":null,"abstract":"<p><p>Regeneration of lost or injured organs is an intriguing process in which numerous cellular events take place to form the new structure. Studies of this process during reconstitution of the intestine have been performed in echinoderms, particularly in holothurians. Many cellular events triggered during regeneration have been described using the sea cucumber <i>Holothuria glaberrima</i> as a research model. More recent experiments have targeted the molecular mechanisms behind the process, a task that has been facilitated by the new sequencing technologies now available. In this review, we present studies involving cellular processes and the genes that have been identified to be associated with the early events of gut regeneration. We also present ongoing efforts to perform functional studies necessary to establish the role(s) of the identified genes. A synopsis of the studies is given with the course of the regenerative process established so far.</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.200227dq","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38477965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}