Author: Krasimir Ivanov Slanchev
Publisher:
ISBN:
Category :
Languages : en
Pages : 154
Book Description
Molecular Mechanisms Governing Germ Line Development in Zebrafish and the Role of this Lineage in Sexual Differentiation
Author: Krasimir Ivanov Slanchev
Publisher:
ISBN:
Category :
Languages : en
Pages : 154
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 154
Book Description
Mechanisms of Germ Cell Formation During Zebrafish Embryogenesis
Author: Fabio Marco D'Orazio
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
In metazoans, the germ fate is acquired during embryogenesis either via oocyte-inherited cytoplasmic aggregates or via chemical induction from the surrounding embryonic cells. Most of the model organisms, including Caenorhabditis elegans, Drosophila melanogaster, Xenopus laevis and Danio rerio, rely on maternal determinants necessary to generate the germ line of the offspring. Although it has been largely established that germ determinants are required for the formation of germ cells, the specific molecular mechanisms driving the onset of the germ line are still unclear. Germ granules have been implicated in transcriptional inhibition contributing to skipping somatic differentiation. Also, epigenetic reprogramming of the embryonic germ line has been shown in several model organisms. However, little is known about the role of the germ plasm in transcription and epigenetics. Here, we show that the germ plasm and the epigenetic landscape of zebrafish primordial germ cells (PGCs) are tightly linked. The early germ line shows similar transcriptional timing, transcriptomic and chromatin profiles with the rest of the embryo and the germ fate is gradually acquired during the first day of development. A PGC-like chromatin profile is acquired while germ plasm re-localises within the cells and PGCs and somatic cells undergo significant epigenetic and transcriptional divergence. By performing time series of chromatin and transcript profiles in the PGCs, we could identify candidate PGC-specific cis-regulatory elements and transcripts. We detect both hypermethylation and chromatin compaction around putative developmental enhancers indicating that the germ fate is acquired avoiding lineage differentiation. Finally, to link epigenetic dynamics to germ plasm behaviour, we inhibited the translation of Tudor Domain 7 (Tdrd7), a germ-plasm-localised protein involved in structural organisation of the germ granules. The mutant embryos reprogram the PGC-specific chromatin state and resemble the somatic cells, suggesting that the germ plasm is primarily responsible for epigenetically preserving the pluripotent state of the PGCs.
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
In metazoans, the germ fate is acquired during embryogenesis either via oocyte-inherited cytoplasmic aggregates or via chemical induction from the surrounding embryonic cells. Most of the model organisms, including Caenorhabditis elegans, Drosophila melanogaster, Xenopus laevis and Danio rerio, rely on maternal determinants necessary to generate the germ line of the offspring. Although it has been largely established that germ determinants are required for the formation of germ cells, the specific molecular mechanisms driving the onset of the germ line are still unclear. Germ granules have been implicated in transcriptional inhibition contributing to skipping somatic differentiation. Also, epigenetic reprogramming of the embryonic germ line has been shown in several model organisms. However, little is known about the role of the germ plasm in transcription and epigenetics. Here, we show that the germ plasm and the epigenetic landscape of zebrafish primordial germ cells (PGCs) are tightly linked. The early germ line shows similar transcriptional timing, transcriptomic and chromatin profiles with the rest of the embryo and the germ fate is gradually acquired during the first day of development. A PGC-like chromatin profile is acquired while germ plasm re-localises within the cells and PGCs and somatic cells undergo significant epigenetic and transcriptional divergence. By performing time series of chromatin and transcript profiles in the PGCs, we could identify candidate PGC-specific cis-regulatory elements and transcripts. We detect both hypermethylation and chromatin compaction around putative developmental enhancers indicating that the germ fate is acquired avoiding lineage differentiation. Finally, to link epigenetic dynamics to germ plasm behaviour, we inhibited the translation of Tudor Domain 7 (Tdrd7), a germ-plasm-localised protein involved in structural organisation of the germ granules. The mutant embryos reprogram the PGC-specific chromatin state and resemble the somatic cells, suggesting that the germ plasm is primarily responsible for epigenetically preserving the pluripotent state of the PGCs.
Germline Development in the Zebrafish
Author: Roland Dosch
Publisher:
ISBN: 9781071609705
Category : Cell differentiation
Languages : en
Pages : 383
Book Description
This volume details a wide range of methods, ranging from beginner through advanced, used to further study zebrafish and fish germline. Chapter guide readers through cultivating and manipulating germ cells, imaging of germline processes and the molecular analysis of their, protein, and RNA. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, application details for both the expert and non-expert reader, and tips on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, Germline Development in the Zebrafish: Methods and Protocols aims to ensure successful results in the further study of this vital field.
Publisher:
ISBN: 9781071609705
Category : Cell differentiation
Languages : en
Pages : 383
Book Description
This volume details a wide range of methods, ranging from beginner through advanced, used to further study zebrafish and fish germline. Chapter guide readers through cultivating and manipulating germ cells, imaging of germline processes and the molecular analysis of their, protein, and RNA. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, application details for both the expert and non-expert reader, and tips on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, Germline Development in the Zebrafish: Methods and Protocols aims to ensure successful results in the further study of this vital field.
Molecular Mechanisms Governing Primordial Germ Cell Migration in Zebrafish
Molecular Mechanisms Governing Primordial Germ Cell Migration in Zebrafish
Author: Maria Doitsidou
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
As a consequence, PGCs in treated embryos were frequently found in Abnormal locations.
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
As a consequence, PGCs in treated embryos were frequently found in Abnormal locations.
Molecular Mechanisms of Zebrafish Sex Differentiation and Sexual Behavior
Molecular Mechanisms in Primordial Germ Cell Development in Zebrafish
Characterization of Germ Line Development in Zebrafish
Author: Arie Koen Braat
Publisher:
ISBN: 9789039320402
Category :
Languages : en
Pages : 121
Book Description
Publisher:
ISBN: 9789039320402
Category :
Languages : en
Pages : 121
Book Description
Investigating Mechanisms of Post-transcriptional Gene Regulation in the Germ Cells of Zebrafish
Author: Sophie Wiszniak
Publisher:
ISBN:
Category : Germ cells
Languages : en
Pages : 192
Book Description
"In most organisms, the primordial germ cells are specified and set aside from the surrounding somatic tissues very early in development. Their ability to carry out a gene regulatory program quite distinct from the surrounding somatic cells, and their capacity to specify entire new organisms has made them a focus of many studies that seek to understand how specific transcriptional and translational programs contribute to cell fate. Zebrafish, a vertebrate with external development of the embryo, is currently one of the best animal models for understanding the molecular basis of germ cell specification. Briefly, germ cell specification is dependent on maternally provided cytoplasmic determinants, termed the germ plasm. The germ plasm, is localised to areas of the embryo that will become the germ cells later in development by inheritance the germ plasm through cleavage divisions. A number of mRNA components of the germ plasm have been identified; interestingly many of them encode RNA-binding proteins, and almost all of them have invertebrate and mammalian orthologues. Evidence suggests that these maternally provided mRNA determinants are specifically maintained in the germ cells throughout embryonic development, and at least some of these gene products are essential for germ cell specification. A number of studies have begun to elucidate the molecular mechanisms that allow germ cell specific maintenance of these mRNAs, and also to identify how maternally provided messages destined for the germ cells are destabilised and eliminated in the somatic tissues. For example, the germ cell specific mRNAs nanos and TDRD7 are destabilised in somatic cells through interactions of the 3 ́UTR sequences with the microRNA miR-430. This miR-430-mediated repression is overcome in germ cells through the binding of an RNA-binding protein Dead end (DND) to distinct sites within the nanos and TDRD7 3 ́UTRs. This thesis details a study of the zebrafish orthologue of HuB, a highly conserved RNAbinding protein with expression in neurons, testes and ovaries in adult vertebrates. In zebrafish, HuB mRNA is maternally provided, and is restricted to the germ cells by 24 hours of development; this is the first report to indicate expression of HuB in the germ cells of vertebrates, suggesting a possible role for HuB in germ cell development. Through detailed mutagenesis studies, the HuB 3 ́UTR has been found to contain a set of four destabilising elements, which bring about somatic degradation of the mRNA, and a separate, 30-nucleotide motif that is responsible for germ cell specific stabilisation of the message. None of these identified destabilising elements are targets for miR-430, and thus they represent novel sequence elements for somatic message degradation in zebrafish. Through a candidate screening approach, DAZL, a germ cell specific RNA-binding protein, was identified as being capable of stabilising HuB mRNA. Further-more, DAZL was shown to mediate this stabilisation of HuB mRNA by interacting, either directly or indirectly, with the 30-nucleotide stabilisation element that was indentified in the HuB 3 ́UTR. This elucidation of the mechanisms of germ cell specific expression of the HuB mRNA is an important finding, for it reveals mechanisms of post-transcriptional regulation that are distinct from that of other germ cell specific mRNAs. In summary, the identification of HuB as a germ cell specific mRNA, and the determination of the post-transcriptional mechanisms responsible for this specific expression is an important first step in understanding how HuB and other germ cell specific RNA-binding proteins contribute to germ cell development and function." -- leaf 3.
Publisher:
ISBN:
Category : Germ cells
Languages : en
Pages : 192
Book Description
"In most organisms, the primordial germ cells are specified and set aside from the surrounding somatic tissues very early in development. Their ability to carry out a gene regulatory program quite distinct from the surrounding somatic cells, and their capacity to specify entire new organisms has made them a focus of many studies that seek to understand how specific transcriptional and translational programs contribute to cell fate. Zebrafish, a vertebrate with external development of the embryo, is currently one of the best animal models for understanding the molecular basis of germ cell specification. Briefly, germ cell specification is dependent on maternally provided cytoplasmic determinants, termed the germ plasm. The germ plasm, is localised to areas of the embryo that will become the germ cells later in development by inheritance the germ plasm through cleavage divisions. A number of mRNA components of the germ plasm have been identified; interestingly many of them encode RNA-binding proteins, and almost all of them have invertebrate and mammalian orthologues. Evidence suggests that these maternally provided mRNA determinants are specifically maintained in the germ cells throughout embryonic development, and at least some of these gene products are essential for germ cell specification. A number of studies have begun to elucidate the molecular mechanisms that allow germ cell specific maintenance of these mRNAs, and also to identify how maternally provided messages destined for the germ cells are destabilised and eliminated in the somatic tissues. For example, the germ cell specific mRNAs nanos and TDRD7 are destabilised in somatic cells through interactions of the 3 ́UTR sequences with the microRNA miR-430. This miR-430-mediated repression is overcome in germ cells through the binding of an RNA-binding protein Dead end (DND) to distinct sites within the nanos and TDRD7 3 ́UTRs. This thesis details a study of the zebrafish orthologue of HuB, a highly conserved RNAbinding protein with expression in neurons, testes and ovaries in adult vertebrates. In zebrafish, HuB mRNA is maternally provided, and is restricted to the germ cells by 24 hours of development; this is the first report to indicate expression of HuB in the germ cells of vertebrates, suggesting a possible role for HuB in germ cell development. Through detailed mutagenesis studies, the HuB 3 ́UTR has been found to contain a set of four destabilising elements, which bring about somatic degradation of the mRNA, and a separate, 30-nucleotide motif that is responsible for germ cell specific stabilisation of the message. None of these identified destabilising elements are targets for miR-430, and thus they represent novel sequence elements for somatic message degradation in zebrafish. Through a candidate screening approach, DAZL, a germ cell specific RNA-binding protein, was identified as being capable of stabilising HuB mRNA. Further-more, DAZL was shown to mediate this stabilisation of HuB mRNA by interacting, either directly or indirectly, with the 30-nucleotide stabilisation element that was indentified in the HuB 3 ́UTR. This elucidation of the mechanisms of germ cell specific expression of the HuB mRNA is an important finding, for it reveals mechanisms of post-transcriptional regulation that are distinct from that of other germ cell specific mRNAs. In summary, the identification of HuB as a germ cell specific mRNA, and the determination of the post-transcriptional mechanisms responsible for this specific expression is an important first step in understanding how HuB and other germ cell specific RNA-binding proteins contribute to germ cell development and function." -- leaf 3.
Mechanisms of Life History Evolution
Author: Thomas Flatt
Publisher: OUP Oxford
ISBN: 0191621021
Category : Science
Languages : en
Pages : 506
Book Description
Life history theory seeks to explain the evolution of the major features of life cycles by analyzing the ecological factors that shape age-specific schedules of growth, reproduction, and survival and by investigating the trade-offs that constrain the evolution of these traits. Although life history theory has made enormous progress in explaining the diversity of life history strategies among species, it traditionally ignores the underlying proximate mechanisms. This novel book argues that many fundamental problems in life history evolution, including the nature of trade-offs, can only be fully resolved if we begin to integrate information on developmental, physiological, and genetic mechanisms into the classical life history framework. Each chapter is written by an established or up-and-coming leader in their respective field; they not only represent the state of the art but also offer fresh perspectives for future research. The text is divided into 7 sections that cover basic concepts (Part 1), the mechanisms that affect different parts of the life cycle (growth, development, and maturation; reproduction; and aging and somatic maintenance) (Parts 2-4), life history plasticity (Part 5), life history integration and trade-offs (Part 6), and concludes with a synthesis chapter written by a prominent leader in the field and an editorial postscript (Part 7).
Publisher: OUP Oxford
ISBN: 0191621021
Category : Science
Languages : en
Pages : 506
Book Description
Life history theory seeks to explain the evolution of the major features of life cycles by analyzing the ecological factors that shape age-specific schedules of growth, reproduction, and survival and by investigating the trade-offs that constrain the evolution of these traits. Although life history theory has made enormous progress in explaining the diversity of life history strategies among species, it traditionally ignores the underlying proximate mechanisms. This novel book argues that many fundamental problems in life history evolution, including the nature of trade-offs, can only be fully resolved if we begin to integrate information on developmental, physiological, and genetic mechanisms into the classical life history framework. Each chapter is written by an established or up-and-coming leader in their respective field; they not only represent the state of the art but also offer fresh perspectives for future research. The text is divided into 7 sections that cover basic concepts (Part 1), the mechanisms that affect different parts of the life cycle (growth, development, and maturation; reproduction; and aging and somatic maintenance) (Parts 2-4), life history plasticity (Part 5), life history integration and trade-offs (Part 6), and concludes with a synthesis chapter written by a prominent leader in the field and an editorial postscript (Part 7).