Christian Mukendi, N. Dean, Rushil Lala, J. Smith, M. Bronner, N. Nikitina
Claudins are major constituents of tight junctions, contributing both to their intercellular sealing and selective permeability properties. While claudins and claudin-like molecules are present in some invertebrates, the association of claudins with tight junctions has been conclusively documented only in vertebrates. Here we report the sequencing, phylogenetic analysis and comprehensive spatiotemporal expression analysis of the entire claudin gene family in the basal extant vertebrate, the sea lamprey. Our results demonstrate that clear orthologues to about half of all mammalian claudins are present in the lamprey, suggesting that at least one round of whole genome duplication contributed to the diversification of this gene family. Expression analysis revealed that claudins are expressed in discrete and specific domains, many of which represent vertebrate-specific innovations, such as in cranial ectodermal placodes and the neural crest; whereas others represent structures characteristic of chordates, e.g. pronephros, notochord, somites, endostyle and pharyngeal arches. By comparing the embryonic expression of claudins in the lamprey to that of other vertebrates, we found that ancestral expression patterns were often preserved in higher vertebrates. Morpholino mediated loss of Cldn3b demonstrated a functional role for this protein in placode and pharyngeal arch morphogenesis. Taken together, our data provide novel insights into the origins and evolution of the claudin gene family and the significance of claudin proteins in the evolution of vertebrates.
{"title":"Evolution of the vertebrate claudin gene family: insights from a basal vertebrate, the sea lamprey.","authors":"Christian Mukendi, N. Dean, Rushil Lala, J. Smith, M. Bronner, N. Nikitina","doi":"10.1387/ijdb.150364nn","DOIUrl":"https://doi.org/10.1387/ijdb.150364nn","url":null,"abstract":"Claudins are major constituents of tight junctions, contributing both to their intercellular sealing and selective permeability properties. While claudins and claudin-like molecules are present in some invertebrates, the association of claudins with tight junctions has been conclusively documented only in vertebrates. Here we report the sequencing, phylogenetic analysis and comprehensive spatiotemporal expression analysis of the entire claudin gene family in the basal extant vertebrate, the sea lamprey. Our results demonstrate that clear orthologues to about half of all mammalian claudins are present in the lamprey, suggesting that at least one round of whole genome duplication contributed to the diversification of this gene family. Expression analysis revealed that claudins are expressed in discrete and specific domains, many of which represent vertebrate-specific innovations, such as in cranial ectodermal placodes and the neural crest; whereas others represent structures characteristic of chordates, e.g. pronephros, notochord, somites, endostyle and pharyngeal arches. By comparing the embryonic expression of claudins in the lamprey to that of other vertebrates, we found that ancestral expression patterns were often preserved in higher vertebrates. Morpholino mediated loss of Cldn3b demonstrated a functional role for this protein in placode and pharyngeal arch morphogenesis. Taken together, our data provide novel insights into the origins and evolution of the claudin gene family and the significance of claudin proteins in the evolution of vertebrates.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"5 2 1","pages":"39-51"},"PeriodicalIF":0.0,"publicationDate":"2016-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91230612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sumiyo Mimura, M. Suga, K. Okada, Masaki Kinehara, H. Nikawa, M. Furue
Neural crest (NC) cells are a group of cells located in the neural folds at the boundary between the neural and epidermal ectoderm. Cranial NC cells migrate to the branchial arches and give rise to the majority of the craniofacial region, whereas trunk and tail NC cells contribute to the heart, enteric ganglia of the gut, melanocytes, sympathetic ganglia, and adrenal chromaffin cells. Positional information is indispensable for the regulation of cranial or trunk and tail NC cells. However, the mechanisms underlying the regulation of positional information during human NC induction have yet to be fully elucidated. In the present study, supplementation of bone morphogenetic protein (BMP) 4 in defined serum-free culture conditions including fibroblast growth factor-2 and Wnt3a from day 8 after NC specification induced the expression of cranial NC markers, AP2alpha, MSX1, and DLX1, during NC cell differentiation from human pluripotent stem cells. On the other hand, the proportion of cells expressing p75(NTR) or HNK1 decreased compared with that of cells cultured without BMP4, whereas gene expression analysis demonstrated that the expression levels of cranial NC-associated genes increased in BMP4-treated NC cells. These BMP4-treated NC cells were capable of differentiation into osteocytes and chondrocytes. The results of the present study indicate that BMP4 regulates cranial positioning during NC development.
{"title":"Bone morphogenetic protein 4 promotes craniofacial neural crest induction from human pluripotent stem cells.","authors":"Sumiyo Mimura, M. Suga, K. Okada, Masaki Kinehara, H. Nikawa, M. Furue","doi":"10.1387/ijdb.160040mk","DOIUrl":"https://doi.org/10.1387/ijdb.160040mk","url":null,"abstract":"Neural crest (NC) cells are a group of cells located in the neural folds at the boundary between the neural and epidermal ectoderm. Cranial NC cells migrate to the branchial arches and give rise to the majority of the craniofacial region, whereas trunk and tail NC cells contribute to the heart, enteric ganglia of the gut, melanocytes, sympathetic ganglia, and adrenal chromaffin cells. Positional information is indispensable for the regulation of cranial or trunk and tail NC cells. However, the mechanisms underlying the regulation of positional information during human NC induction have yet to be fully elucidated. In the present study, supplementation of bone morphogenetic protein (BMP) 4 in defined serum-free culture conditions including fibroblast growth factor-2 and Wnt3a from day 8 after NC specification induced the expression of cranial NC markers, AP2alpha, MSX1, and DLX1, during NC cell differentiation from human pluripotent stem cells. On the other hand, the proportion of cells expressing p75(NTR) or HNK1 decreased compared with that of cells cultured without BMP4, whereas gene expression analysis demonstrated that the expression levels of cranial NC-associated genes increased in BMP4-treated NC cells. These BMP4-treated NC cells were capable of differentiation into osteocytes and chondrocytes. The results of the present study indicate that BMP4 regulates cranial positioning during NC development.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"22 1","pages":"21-8"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73522899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aisha Abduelmula, Ruijin Huang, Q. Pu, H. Tamamura, Gabriela Morosan-Puopolo, B. Brand-Saberi
Stromal-cell-derived factor-1 (SDF-1), the only ligand of the chemokine receptor CXCR4, is involved in skeletal muscle development. However, its role in the proliferation, differentiation and migration of somite cells is not well understood. Here, we investigated its function during somite development in chicken embryos by using gain-of-function and loss-of-function experiments. Overexpression of SDF-1 was performed by electroporating SDF-1 constructs into the ventrolateral part of the somite, or by injecting SDF-1-expressing cells into the somites of stages HH14-16 chicken embryos. We found that enhanced SDF-1 signaling induced cell proliferation in the somite. This resulted in an increase in number of both myotomal and endothelial cells. In contrast, inhibition of SDF-1/CXCR4 signaling led to a reduction of myotomal cells. Injection of SDF-1 producing cells into the somite induced ectopic localization of myotomal cells in the sclerotome. Although many SDF-1-expressing somite cells colonized the limb, only a few of them developed into muscle cells. This resulted in a reduction of the limb muscle mass. This means that most myogenic progenitors were stopped on their migration towards the limb due to the high concentration of the SDF-1 signal in the somite. Most of the SDF-1-expressing somite cells found in the limb were of endothelial cell fate and they contributed to the increase in limb blood vessels. These results reveal that SDF-1 promotes the proliferation of both myogenic and angiogenic progenitor cells of the somite and controls myotome formation. Furthermore, SDF-1 controls muscle and blood vessel formation in the limb in different ways.
{"title":"SDF-1 controls the muscle and blood vessel formation of the somite.","authors":"Aisha Abduelmula, Ruijin Huang, Q. Pu, H. Tamamura, Gabriela Morosan-Puopolo, B. Brand-Saberi","doi":"10.1387/ijdb.150132rh","DOIUrl":"https://doi.org/10.1387/ijdb.150132rh","url":null,"abstract":"Stromal-cell-derived factor-1 (SDF-1), the only ligand of the chemokine receptor CXCR4, is involved in skeletal muscle development. However, its role in the proliferation, differentiation and migration of somite cells is not well understood. Here, we investigated its function during somite development in chicken embryos by using gain-of-function and loss-of-function experiments. Overexpression of SDF-1 was performed by electroporating SDF-1 constructs into the ventrolateral part of the somite, or by injecting SDF-1-expressing cells into the somites of stages HH14-16 chicken embryos. We found that enhanced SDF-1 signaling induced cell proliferation in the somite. This resulted in an increase in number of both myotomal and endothelial cells. In contrast, inhibition of SDF-1/CXCR4 signaling led to a reduction of myotomal cells. Injection of SDF-1 producing cells into the somite induced ectopic localization of myotomal cells in the sclerotome. Although many SDF-1-expressing somite cells colonized the limb, only a few of them developed into muscle cells. This resulted in a reduction of the limb muscle mass. This means that most myogenic progenitors were stopped on their migration towards the limb due to the high concentration of the SDF-1 signal in the somite. Most of the SDF-1-expressing somite cells found in the limb were of endothelial cell fate and they contributed to the increase in limb blood vessels. These results reveal that SDF-1 promotes the proliferation of both myogenic and angiogenic progenitor cells of the somite and controls myotome formation. Furthermore, SDF-1 controls muscle and blood vessel formation in the limb in different ways.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"37 1","pages":"29-38"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87455486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Marracci, A. Vangelisti, V. Raffa, M. Andreazzoli, L. Dente
Pdzrn3, a multidomain protein with E3-ubiquitin ligase activity, has been reported to play a role in myoblast and osteoblast differentiation and, more recently, in neuronal and endothelial cell development. The expression of the pdzrn3 gene is developmentally regulated in various vertebrate tissues, including muscular, neural and vascular system. Little is known about its expression during kidney development, although genetic polymorphisms and alterations around the human pdzrn3 chromosomal region have been found to be associated with renal cell carcinomas and other kidney diseases. We investigated the pdzrn3 spatio-temporal expression pattern in Xenopus laevis embryos by in situ hybridization. We focused our study on the development of the pronephros, which is the embryonic amphibian kidney, functionally similar to the most primitive nephric structures of human kidney. To explore the role of pdzrn3 during renal morphogenesis, we performed loss-of-function experiments, through antisense morpholino injections and analysed the morphants using specific pronephric markers. Dynamic pdzrn3 expression was observed in embryonic tissues, such as somites, brain, eye, blood islands, heart, liver and pronephros. Loss of function experiments resulted in specific alterations of pronephros development. In particular, at early stages, pdzrn3 depletion was associated with a reduction of the pronephros anlagen and later, with perturbations of the tubulogenesis, including deformation of the proximal tubules. Rescue experiments, in which mRNA of the zebrafish pdzrn3 orthologue was injected together with the morpholino, allowed recovery of the kidney phenotypes. These results underline the importance of pdzrn3 expression for correct nephrogenesis.
{"title":"pdzrn3 is required for pronephros morphogenesis in Xenopus laevis.","authors":"S. Marracci, A. Vangelisti, V. Raffa, M. Andreazzoli, L. Dente","doi":"10.1387/ijdb.150381ld","DOIUrl":"https://doi.org/10.1387/ijdb.150381ld","url":null,"abstract":"Pdzrn3, a multidomain protein with E3-ubiquitin ligase activity, has been reported to play a role in myoblast and osteoblast differentiation and, more recently, in neuronal and endothelial cell development. The expression of the pdzrn3 gene is developmentally regulated in various vertebrate tissues, including muscular, neural and vascular system. Little is known about its expression during kidney development, although genetic polymorphisms and alterations around the human pdzrn3 chromosomal region have been found to be associated with renal cell carcinomas and other kidney diseases. We investigated the pdzrn3 spatio-temporal expression pattern in Xenopus laevis embryos by in situ hybridization. We focused our study on the development of the pronephros, which is the embryonic amphibian kidney, functionally similar to the most primitive nephric structures of human kidney. To explore the role of pdzrn3 during renal morphogenesis, we performed loss-of-function experiments, through antisense morpholino injections and analysed the morphants using specific pronephric markers. Dynamic pdzrn3 expression was observed in embryonic tissues, such as somites, brain, eye, blood islands, heart, liver and pronephros. Loss of function experiments resulted in specific alterations of pronephros development. In particular, at early stages, pdzrn3 depletion was associated with a reduction of the pronephros anlagen and later, with perturbations of the tubulogenesis, including deformation of the proximal tubules. Rescue experiments, in which mRNA of the zebrafish pdzrn3 orthologue was injected together with the morpholino, allowed recovery of the kidney phenotypes. These results underline the importance of pdzrn3 expression for correct nephrogenesis.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"143 1","pages":"57-63"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80322190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The advent of human pluripotent stem cells, with the first derivation of human embryonic stem cells in 1998, and of human induced pluripotent stem cells in 2007, has ushered in an era of considerable excitement about the prospects of using these cells to develop new opportunities for healthcare, from their potential for regenerative medicine to their use as tools for studying the cellular basis of many diseases and the discovery of new drugs. But as with the flowering of many new areas in science, the biology of human pluripotent stem cells has its roots in a long history of, sometimes, less fêted research. In a period when research funding is frequently driven by a desire to meet specific clinical or economic goals, it is salutary to remember that the opportunities offered by human pluripotent stem cells have their origins in curiosity driven research without any of those goals in mind. In this case, that research focused on the relatively rare gonadal cancers known as teratomas, tumors that have fascinated people since antiquity because their sometime grotesque manifestations with haphazard collections of tissues and sometimes recognizable body parts. Although well known to clinical pathologists it was the pioneering work of Leroy Stevens, who first discovered that teratomas occur at a significant rate in the 129 strain of the laboratory mouse and could be produced experimentally, that laid the foundations for our understanding of the biology of these tumors and the central role of the embryonal carcinoma cell, one of the archetypal tumor stem cells.
{"title":"Pluripotent human stem cells: Standing on the shoulders of giants.","authors":"I. Damjanov, P. Andrews","doi":"10.1387/ijdb.160437id","DOIUrl":"https://doi.org/10.1387/ijdb.160437id","url":null,"abstract":"The advent of human pluripotent stem cells, with the first derivation of human embryonic stem cells in 1998, and of human induced pluripotent stem cells in 2007, has ushered in an era of considerable excitement about the prospects of using these cells to develop new opportunities for healthcare, from their potential for regenerative medicine to their use as tools for studying the cellular basis of many diseases and the discovery of new drugs. But as with the flowering of many new areas in science, the biology of human pluripotent stem cells has its roots in a long history of, sometimes, less fêted research. In a period when research funding is frequently driven by a desire to meet specific clinical or economic goals, it is salutary to remember that the opportunities offered by human pluripotent stem cells have their origins in curiosity driven research without any of those goals in mind. In this case, that research focused on the relatively rare gonadal cancers known as teratomas, tumors that have fascinated people since antiquity because their sometime grotesque manifestations with haphazard collections of tissues and sometimes recognizable body parts. Although well known to clinical pathologists it was the pioneering work of Leroy Stevens, who first discovered that teratomas occur at a significant rate in the 129 strain of the laboratory mouse and could be produced experimentally, that laid the foundations for our understanding of the biology of these tumors and the central role of the embryonal carcinoma cell, one of the archetypal tumor stem cells.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"92 1","pages":"321-325"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73381909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Graham, D. Solter, J. Gearhart, J. Nadeau, B. Knowles
In 2016, a symposium was convened in Leroy C. Stevens' honor, in association with a meeting of the International Stem Cell Initiative (ISCI). ISCI, funded internationally, is composed of a group of ~100 scientists from many countries, under the leadership of Peter Andrews, who have worked together to characterize a significant number of human pluripotent stem cell lines, to monitor their genetic stability and their differentiation into mature cell types and tissues in vitro and in vivo. Those at the ISCI meeting puzzled through one of the thorniest problems in the therapeutic use of the differentiated derivatives of pluripotent stem cells for human therapy; namely, pluripotent stem cells can differentiate into any cell type in the adult organism, but they also have the capacity for unlimited self-renewal, hence if mutated they may have tumorigenic potential. The meeting considered how these cells might become genetically or epigenetically abnormal and how the safety of these cells for human therapeutic uses could be assessed and assured. The symposium was an opportunity to pay tribute to Leroy Stevens and to the basic science origins of this newest aspect of regenerative medicine. It was a time to reflect on the past and on how it can influence the future of our field.
2016年，在Leroy C. Stevens的荣誉下，与国际干细胞倡议(ISCI)会议联合召开了一次研讨会。ISCI由来自多个国家的约100名科学家组成，在Peter Andrews的领导下，他们共同研究了大量人类多能干细胞系的特征，监测了它们的遗传稳定性以及它们在体外和体内向成熟细胞类型和组织的分化。参加ISCI会议的人对多能干细胞分化衍生物用于人类治疗的最棘手的问题之一感到困惑;也就是说，多能干细胞可以在成年生物体中分化成任何类型的细胞，但它们也具有无限自我更新的能力，因此，如果发生突变，它们可能具有致瘤潜力。会议审议了这些细胞如何在遗传或表观遗传上变得异常，以及如何评估和确保这些细胞用于人类治疗的安全性。这次研讨会是一次向Leroy Stevens致敬的机会，也是一次向再生医学这一最新领域的基础科学起源致敬的机会。这是一个反思过去以及它将如何影响我们这个领域未来的时刻。
{"title":"Honoring the work and life of Leroy C. Stevens. A symposium as part of the International Stem Cell Initiative Workshop.","authors":"C. Graham, D. Solter, J. Gearhart, J. Nadeau, B. Knowles","doi":"10.1387/ijdb.160420bk","DOIUrl":"https://doi.org/10.1387/ijdb.160420bk","url":null,"abstract":"In 2016, a symposium was convened in Leroy C. Stevens' honor, in association with a meeting of the International Stem Cell Initiative (ISCI). ISCI, funded internationally, is composed of a group of ~100 scientists from many countries, under the leadership of Peter Andrews, who have worked together to characterize a significant number of human pluripotent stem cell lines, to monitor their genetic stability and their differentiation into mature cell types and tissues in vitro and in vivo. Those at the ISCI meeting puzzled through one of the thorniest problems in the therapeutic use of the differentiated derivatives of pluripotent stem cells for human therapy; namely, pluripotent stem cells can differentiate into any cell type in the adult organism, but they also have the capacity for unlimited self-renewal, hence if mutated they may have tumorigenic potential. The meeting considered how these cells might become genetically or epigenetically abnormal and how the safety of these cells for human therapeutic uses could be assessed and assured. The symposium was an opportunity to pay tribute to Leroy Stevens and to the basic science origins of this newest aspect of regenerative medicine. It was a time to reflect on the past and on how it can influence the future of our field.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"67 1","pages":"327-336"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76517765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yu Xue, Cencan Xing, Wenjuan Zhang, Can-bin Chen, Jingjin Xu, A. Meng, Yutian Pan
A vertebrate signaling center, known in zebrafish as the organizer, is essential for axis patterning and formation and is regulated by multiple cell signaling pathways, including Wnt, Nodal, and Bmp. Organizer-specific Bmp2b plays important roles in the maintenance of the Bmp activity gradient and dorsal-ventral patterning. However, it is unknown how transcription of bmp2b in the organizer is regulated. In this study, we generated a bmp2b transgenic line Tsg(-2.272bmp2b:gfp) that reproduced organizer-specific bmp2b expression. Dissection analysis revealed that a 0.273-kb minimal promoter was indispensable for bmp2b expression in the dorsal organizer. Reporter assays showed that organizer-specific bmp2b is negatively regulated by the Nodal signal and positively regulated by the Wnt signal in both embryos and cell lines. Promoter analysis and chromatin-immunoprecipitation (ChIP) indicated that one consensus Smad-binding element (SBE) (CAGAC) and one Lef/Tcf-binding element (LBE) (AGATAA) were present in the 0.273-kb promoter, and could be directly bound by Smad2 and β-catenin proteins. Together, these results suggest that maintenance of organizer-specific bmp2b expression involves opposite and concerted regulation by Nodal and Wnt signaling.
{"title":"Coordinate involvement of Nodal-dependent inhibition and Wnt-dependent activation in the maintenance of organizer-specific bmp2b in zebrafish.","authors":"Yu Xue, Cencan Xing, Wenjuan Zhang, Can-bin Chen, Jingjin Xu, A. Meng, Yutian Pan","doi":"10.1387/ijdb.150193yx","DOIUrl":"https://doi.org/10.1387/ijdb.150193yx","url":null,"abstract":"A vertebrate signaling center, known in zebrafish as the organizer, is essential for axis patterning and formation and is regulated by multiple cell signaling pathways, including Wnt, Nodal, and Bmp. Organizer-specific Bmp2b plays important roles in the maintenance of the Bmp activity gradient and dorsal-ventral patterning. However, it is unknown how transcription of bmp2b in the organizer is regulated. In this study, we generated a bmp2b transgenic line Tsg(-2.272bmp2b:gfp) that reproduced organizer-specific bmp2b expression. Dissection analysis revealed that a 0.273-kb minimal promoter was indispensable for bmp2b expression in the dorsal organizer. Reporter assays showed that organizer-specific bmp2b is negatively regulated by the Nodal signal and positively regulated by the Wnt signal in both embryos and cell lines. Promoter analysis and chromatin-immunoprecipitation (ChIP) indicated that one consensus Smad-binding element (SBE) (CAGAC) and one Lef/Tcf-binding element (LBE) (AGATAA) were present in the 0.273-kb promoter, and could be directly bound by Smad2 and β-catenin proteins. Together, these results suggest that maintenance of organizer-specific bmp2b expression involves opposite and concerted regulation by Nodal and Wnt signaling.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"5 1","pages":"13-9"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87657693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The nucleolar protein 4-like (NOL4L) gene is present on chromosome 20 (20q11.21) in humans. Parts of this gene have been shown to fuse with RUNX1 and PAX5 in acute myeloid leukemia and acute lymphoblastic leukemia, respectively. The normal function of NOL4L in humans and other organisms is not well understood. The expression patterns and functions of NOL4L homologs during vertebrate development have not been reported. We sought to address these questions by studying the expression pattern of zebrafish nol4l during embryogenesis. Our data show that Znol4l mRNA is expressed in multiple organs in zebrafish embryos. The sites of expression include parts of the brain, spinal cord, pronephros, hematopoietic cells and gut.
{"title":"Nucleolar protein 4-like has a complex expression pattern in zebrafish embryos.","authors":"S. Borah, Praveen Barrodia, R. Swain","doi":"10.1387/ijdb.150307rs","DOIUrl":"https://doi.org/10.1387/ijdb.150307rs","url":null,"abstract":"The nucleolar protein 4-like (NOL4L) gene is present on chromosome 20 (20q11.21) in humans. Parts of this gene have been shown to fuse with RUNX1 and PAX5 in acute myeloid leukemia and acute lymphoblastic leukemia, respectively. The normal function of NOL4L in humans and other organisms is not well understood. The expression patterns and functions of NOL4L homologs during vertebrate development have not been reported. We sought to address these questions by studying the expression pattern of zebrafish nol4l during embryogenesis. Our data show that Znol4l mRNA is expressed in multiple organs in zebrafish embryos. The sites of expression include parts of the brain, spinal cord, pronephros, hematopoietic cells and gut.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"45 1","pages":"53-6"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88622096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Jevtić, A. Milunović-Jevtić, Matthew R. Dilsaver, J. Gatlin, D. Levy
Striking size variations are prominent throughout biology, at the organismal, cellular, and subcellular levels. Important fundamental questions concern organelle size regulation and how organelle size is regulated relative to cell size, also known as scaling. Uncovering mechanisms of organelle size regulation will inform the functional significance of size as well as the implications of misregulated size, for instance in the case of nuclear enlargement in cancer. Xenopus egg and embryo extracts are powerful cell-free systems that have been utilized extensively for mechanistic and functional studies of various organelles and subcellular structures. The open biochemical nature of the extract permits facile manipulation of its composition, and in recent years extract approaches have illuminated mechanisms of organelle size regulation. This review largely focuses on in vitro Xenopus studies that have identified regulators of nuclear and spindle size. We also discuss potential relationships between size scaling of the nucleus and spindle, size regulation of other subcellular structures, and extract experiments that have clarified developmental timing mechanisms. We conclude by offering some future prospects, notably the integration of Xenopus extract with microfluidic technology.
{"title":"Use of Xenopus cell-free extracts to study size regulation of subcellular structures.","authors":"P. Jevtić, A. Milunović-Jevtić, Matthew R. Dilsaver, J. Gatlin, D. Levy","doi":"10.1387/IJDB.160158DL","DOIUrl":"https://doi.org/10.1387/IJDB.160158DL","url":null,"abstract":"Striking size variations are prominent throughout biology, at the organismal, cellular, and subcellular levels. Important fundamental questions concern organelle size regulation and how organelle size is regulated relative to cell size, also known as scaling. Uncovering mechanisms of organelle size regulation will inform the functional significance of size as well as the implications of misregulated size, for instance in the case of nuclear enlargement in cancer. Xenopus egg and embryo extracts are powerful cell-free systems that have been utilized extensively for mechanistic and functional studies of various organelles and subcellular structures. The open biochemical nature of the extract permits facile manipulation of its composition, and in recent years extract approaches have illuminated mechanisms of organelle size regulation. This review largely focuses on in vitro Xenopus studies that have identified regulators of nuclear and spindle size. We also discuss potential relationships between size scaling of the nucleus and spindle, size regulation of other subcellular structures, and extract experiments that have clarified developmental timing mechanisms. We conclude by offering some future prospects, notably the integration of Xenopus extract with microfluidic technology.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"23 1","pages":"277-288"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78643666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The parental genomes are initially spatially separated in each pronucleus after fertilization. Here we have used green-to-red photoconversion of Dendra2-H2B-labeled pronuclei to distinguish maternal and paternal chromatin domains and to track their spatial distribution in living Caenorhabditis elegans embryos starting shortly after fertilization. Intermingling of the parental chromatin did not occur until after the division of the AB and P1 blastomeres, at the 4-cell stage. Unexpectedly, we observed that the intermingling of chromatin did not take place during mitosis or during chromatin decondensation, but rather ∼ 3-5 minutes into the cell cycle. Furthermore, unlike what has been observed in mammalian cells, the relative spatial positioning of chromatin domains remained largely unchanged during prometaphase in the early C. elegans embryo. Live imaging of photoconverted chromatin also allowed us to detect a reproducible 180° rotation of the nuclei during cytokinesis of the one-cell embryo. Imaging of fluorescently-labeled P granules and polar bodies showed that the entire embryo rotates during the first cell division. To our knowledge, we report here the first live observation of the initial separation and subsequent mixing of parental chromatin domains during embryogenesis.
{"title":"Live imaging reveals spatial separation of parental chromatin until the four-cell stage in Caenorhabditis elegans embryos.","authors":"Jitka Bolková, C. Lanctôt","doi":"10.1387/ijdb.150222cl","DOIUrl":"https://doi.org/10.1387/ijdb.150222cl","url":null,"abstract":"The parental genomes are initially spatially separated in each pronucleus after fertilization. Here we have used green-to-red photoconversion of Dendra2-H2B-labeled pronuclei to distinguish maternal and paternal chromatin domains and to track their spatial distribution in living Caenorhabditis elegans embryos starting shortly after fertilization. Intermingling of the parental chromatin did not occur until after the division of the AB and P1 blastomeres, at the 4-cell stage. Unexpectedly, we observed that the intermingling of chromatin did not take place during mitosis or during chromatin decondensation, but rather ∼ 3-5 minutes into the cell cycle. Furthermore, unlike what has been observed in mammalian cells, the relative spatial positioning of chromatin domains remained largely unchanged during prometaphase in the early C. elegans embryo. Live imaging of photoconverted chromatin also allowed us to detect a reproducible 180° rotation of the nuclei during cytokinesis of the one-cell embryo. Imaging of fluorescently-labeled P granules and polar bodies showed that the entire embryo rotates during the first cell division. To our knowledge, we report here the first live observation of the initial separation and subsequent mixing of parental chromatin domains during embryogenesis.","PeriodicalId":94228,"journal":{"name":"The International journal of developmental biology","volume":"98 1","pages":"5-12"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84125744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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