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Matthias Hammerschmidt - One of the best experts on this subject based on the ideXlab platform.
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how to make a teleost Adenohypophysis molecular pathways of pituitary development in zebrafish
Molecular and Cellular Endocrinology, 2009Co-Authors: Hans-martin Pogoda, Matthias HammerschmidtAbstract:Abstract The anterior pituitary gland, or Adenohypophysis (AH), represents the key component of the vertebrate hypothalamo–hypophyseal axis, where it functions at the interphase of the nervous and endocrine system to regulate basic body functions like growth, metabolism and reproduction. For developmental biologists, the Adenohypophysis serves as an excellent model system for the studies of organogenesis and differential cell fate specification. Previous research, mainly done in mouse, identified numerous extrinsic signaling cues and intrinsic transcription factors that orchestrate the gland's developmental progression. In the past years, the zebrafish has emerged as a powerful tool to elucidate the genetic networks controlling vertebrate development, behavior and disease. Based on mutants isolated in forward genetic screens and on gene knock-downs using morpholino oligonucleotide (oligo) antisense technology, our current understanding of the molecular machinery driving adenohypophyseal ontogeny could be considerably improved. In addition, comparative analyses have shed further light onto the evolution of this rather recently invented organ. The goal of this review is to summarize current knowledge of the genetic and molecular control of zebrafish pituitary development, with special focus on most recent findings, including some thus far unpublished data from our own laboratory on the transcription factor Six1. In addition, zebrafish data will be discussed in comparison with current understanding of Adenohypophysis development in mouse.
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How to make a Teleost Adenohypophysis: Molecular Pathways of Pituitary development in Zebrafish
Molecular and Cellular Endocrinology, 2009Co-Authors: Hans-martin Pogoda, Matthias HammerschmidtAbstract:The anterior pituitary gland, or Adenohypophysis, represents the key component of the vertebrate hypothalamo-hypophyseal axis, where it functions at the interphase of the nervous and endocrine system to regulate basic body functions like growth, metabolism and reproduction. For developmental biologists, the Adenohypophysis serves as an excellent model system for the studies of organogenesis and differential cell fate specification. Previous research, mainly done in mouse, identified numerous extrinsic signaling cues and intrinsic transcription factors that orchestrate the gland's developmental progression.
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The proneural gene ascl1a is required for endocrine differentiation and cell survival in the zebrafish Adenohypophysis
Development, 2006Co-Authors: Hans-martin Pogoda, Wiebke Herzog, Sophia Von Der Hardt, Carina Kramer, Heinz Schwarz, Matthias HammerschmidtAbstract:Mammalian basic helix-loop-helix proteins of the achaete-scute family are proneural factors that, in addition to the central nervous system, are required for the differentiation of peripheral neurons and sensory cells, derivatives of the neural crest and placodal ectoderm. Here, in identifying the molecular nature of the pia mutation, we investigate the role of the zebrafish achaete-scute homologue ascl1a during development of the Adenohypophysis, an endocrine derivative of the placodal ectoderm. Similar to mutants deficient in Fgf3 signaling from the adjacent ventral diencepahalon, pia mutants display failure of endocrine differentiation of all adenohypophyseal cell types. Shortly after the failed first phase of cell differentiation, the Adenohypophysis of pia mutants displays a transient phase of cell death, which affects most, but not all adenohypophyseal cells. Surviving cells form a smaller pituitary rudiment, lack expression of specific adenohypophyseal marker genes ( pit1, neurod ), while expressing others ( lim3, pitx3 ), and display an ultrastructure reminiscent of precursor cells. During normal development, ascl1a is expressed in the Adenohypophysis and the adjacent diencephalon, the source of Fgf3 signals. However, chimera analyses show that ascl1a is required cell-autonomously in adenohypophyseal cells themselves. In fgf3 mutants, adenohypophyseal expression of ascl1a is absent, while implantation of Fgf3-soaked beads into pia mutants enhances ascl1a , but fails to rescue pit1 expression. Together, this suggests that Ascl1a might act downstream of diencephalic Fgf3 signaling to mediate some of the effects of Fgf3 on the developing Adenohypophysis.
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zebrafish pit1 mutants lack three pituitary cell types and develop severe dwarfism
Molecular Endocrinology, 2004Co-Authors: Gabriela Nica, Wiebke Herzog, Carmen Sonntag, Matthias HammerschmidtAbstract:The Pou domain transcription factor Pit-1 is required for lineage determination and cellular commitment processes during mammalian Adenohypophysis development. Here we report the cloning and mutational analysis of a pit1 homolog from zebrafish. Compared with mouse, zebrafish pit1 starts to be expressed at a much earlier stage of Adenohypophysis development. However, as in the mouse, expression is restricted to a subset of pituitary cell types, excluding proopiomelanocortin (pomc)-expressing cells (corticotropes, melanotropes) and possibly gonadotropes. We could identify two N-ethyl-N-nitrosourea-induced zebrafish pit1 null mutants. Most mutants die during larval stages, whereas survivors develop severe dwarfism. Mutant larvae lack lactotropes, somatotropes, and thyrotropes, although the Adenohypophysis is of normal size, without any sign of increased apoptosis rates. Instead, mutant embryos initiate ectopic expression of pomc in pit1-positive cells, leading to an expansion of the Pomc lineage. Similarly, ...
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Genetic Analysis of Adenohypophysis Formation in Zebrafish
Molecular Endocrinology, 2004Co-Authors: Wiebke Herzog, Carmen Sonntag, Brigitte Walderich, Jörg Odenthal, Hans-martin Maischein, Matthias HammerschmidtAbstract:The Adenohypophysis consists of at least six different cell types, somatotropes, lactotropes, thyrotropes, melanotropes, corticotropes, and gonadotropes. In mouse, cloning of spontaneous mutations and gene targeting has revealed multiple genes required for different steps of Adenohypophysis development. Here, we report the results of a systematic search for genes required for Adenohypophysis formation and patterning in zebrafish. By screening F3 offspring of N-ethyl-N-nitrosourea-mutagenized founder fish, we isolated eleven mutants with absent or reduced expression of GH, the product of somatotropes, but a normally developing hypothalamus. Of such mutants, eight were further analyzed and mapped. They define four genes essential for different steps of Adenohypophysis development. Two of them, lia and pia, affect the entire Adenohypophysis, whereas the other two are required for a subset of adenohypophyseal cell types only. The third gene is zebrafish pit1 and is required for lactotropes, thyrotropes, and s...
Hans-martin Pogoda - One of the best experts on this subject based on the ideXlab platform.
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how to make a teleost Adenohypophysis molecular pathways of pituitary development in zebrafish
Molecular and Cellular Endocrinology, 2009Co-Authors: Hans-martin Pogoda, Matthias HammerschmidtAbstract:Abstract The anterior pituitary gland, or Adenohypophysis (AH), represents the key component of the vertebrate hypothalamo–hypophyseal axis, where it functions at the interphase of the nervous and endocrine system to regulate basic body functions like growth, metabolism and reproduction. For developmental biologists, the Adenohypophysis serves as an excellent model system for the studies of organogenesis and differential cell fate specification. Previous research, mainly done in mouse, identified numerous extrinsic signaling cues and intrinsic transcription factors that orchestrate the gland's developmental progression. In the past years, the zebrafish has emerged as a powerful tool to elucidate the genetic networks controlling vertebrate development, behavior and disease. Based on mutants isolated in forward genetic screens and on gene knock-downs using morpholino oligonucleotide (oligo) antisense technology, our current understanding of the molecular machinery driving adenohypophyseal ontogeny could be considerably improved. In addition, comparative analyses have shed further light onto the evolution of this rather recently invented organ. The goal of this review is to summarize current knowledge of the genetic and molecular control of zebrafish pituitary development, with special focus on most recent findings, including some thus far unpublished data from our own laboratory on the transcription factor Six1. In addition, zebrafish data will be discussed in comparison with current understanding of Adenohypophysis development in mouse.
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How to make a Teleost Adenohypophysis: Molecular Pathways of Pituitary development in Zebrafish
Molecular and Cellular Endocrinology, 2009Co-Authors: Hans-martin Pogoda, Matthias HammerschmidtAbstract:The anterior pituitary gland, or Adenohypophysis, represents the key component of the vertebrate hypothalamo-hypophyseal axis, where it functions at the interphase of the nervous and endocrine system to regulate basic body functions like growth, metabolism and reproduction. For developmental biologists, the Adenohypophysis serves as an excellent model system for the studies of organogenesis and differential cell fate specification. Previous research, mainly done in mouse, identified numerous extrinsic signaling cues and intrinsic transcription factors that orchestrate the gland's developmental progression.
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The proneural gene ascl1a is required for endocrine differentiation and cell survival in the zebrafish Adenohypophysis
Development, 2006Co-Authors: Hans-martin Pogoda, Wiebke Herzog, Sophia Von Der Hardt, Carina Kramer, Heinz Schwarz, Matthias HammerschmidtAbstract:Mammalian basic helix-loop-helix proteins of the achaete-scute family are proneural factors that, in addition to the central nervous system, are required for the differentiation of peripheral neurons and sensory cells, derivatives of the neural crest and placodal ectoderm. Here, in identifying the molecular nature of the pia mutation, we investigate the role of the zebrafish achaete-scute homologue ascl1a during development of the Adenohypophysis, an endocrine derivative of the placodal ectoderm. Similar to mutants deficient in Fgf3 signaling from the adjacent ventral diencepahalon, pia mutants display failure of endocrine differentiation of all adenohypophyseal cell types. Shortly after the failed first phase of cell differentiation, the Adenohypophysis of pia mutants displays a transient phase of cell death, which affects most, but not all adenohypophyseal cells. Surviving cells form a smaller pituitary rudiment, lack expression of specific adenohypophyseal marker genes ( pit1, neurod ), while expressing others ( lim3, pitx3 ), and display an ultrastructure reminiscent of precursor cells. During normal development, ascl1a is expressed in the Adenohypophysis and the adjacent diencephalon, the source of Fgf3 signals. However, chimera analyses show that ascl1a is required cell-autonomously in adenohypophyseal cells themselves. In fgf3 mutants, adenohypophyseal expression of ascl1a is absent, while implantation of Fgf3-soaked beads into pia mutants enhances ascl1a , but fails to rescue pit1 expression. Together, this suggests that Ascl1a might act downstream of diencephalic Fgf3 signaling to mediate some of the effects of Fgf3 on the developing Adenohypophysis.
Mario Pestarino - One of the best experts on this subject based on the ideXlab platform.
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expression of the amphioxus pit 1 gene amphipou1f1 pit 1 exclusively in the developing preoral organ a putative homolog of the vertebrate Adenohypophysis
Brain Research Bulletin, 2008Co-Authors: Simona Candiani, Nicholas D Holland, Diana Oliveri, Manuela Parodi, Mario PestarinoAbstract:For the Florida amphioxus (Branchiostoma floridae), the full-length sequence and developmental expression of AmphiPOU1F1/Pit-1 are described. This gene, which is present in a single copy in the genome, is homologous to Pit-1 genes of vertebrates that play key roles in the development of the Adenohypophysis. During amphioxus development, AmphiPOU1F1/Pit-1 transcripts are limited to Hatschek's left diverticulum and the larval tissue developing from it--namely the concave portion of the preoral organ. No other expression domains for this gene were detected during embryonic and larval development. From data currently available for hemichordates, amphioxus and ascidians, the best supported homologs for the vertebrate Adenohypophysis are the preoral ciliary organ of hemichordates, preoral organ/Hatschek's pit of amphioxus and the neural gland/duct complex of ascidians. Better insights into pituitary evolution will require additional information: for invertebrate deuterostomes, more of the key pituitary genes in hemichordates and tunicates need to be studied; for the more basal groups vertebrates, it will be important to determine whether the source of the Adenohypophysis is endodermal or ectodermal and to demonstrate what, if any, contribution mesodermal head coeloms might make to the developing pituitary.
Simona Candiani - One of the best experts on this subject based on the ideXlab platform.
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expression of the amphioxus pit 1 gene amphipou1f1 pit 1 exclusively in the developing preoral organ a putative homolog of the vertebrate Adenohypophysis
Brain Research Bulletin, 2008Co-Authors: Simona Candiani, Nicholas D Holland, Diana Oliveri, Manuela Parodi, Mario PestarinoAbstract:For the Florida amphioxus (Branchiostoma floridae), the full-length sequence and developmental expression of AmphiPOU1F1/Pit-1 are described. This gene, which is present in a single copy in the genome, is homologous to Pit-1 genes of vertebrates that play key roles in the development of the Adenohypophysis. During amphioxus development, AmphiPOU1F1/Pit-1 transcripts are limited to Hatschek's left diverticulum and the larval tissue developing from it--namely the concave portion of the preoral organ. No other expression domains for this gene were detected during embryonic and larval development. From data currently available for hemichordates, amphioxus and ascidians, the best supported homologs for the vertebrate Adenohypophysis are the preoral ciliary organ of hemichordates, preoral organ/Hatschek's pit of amphioxus and the neural gland/duct complex of ascidians. Better insights into pituitary evolution will require additional information: for invertebrate deuterostomes, more of the key pituitary genes in hemichordates and tunicates need to be studied; for the more basal groups vertebrates, it will be important to determine whether the source of the Adenohypophysis is endodermal or ectodermal and to demonstrate what, if any, contribution mesodermal head coeloms might make to the developing pituitary.
Manuela Parodi - One of the best experts on this subject based on the ideXlab platform.
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expression of the amphioxus pit 1 gene amphipou1f1 pit 1 exclusively in the developing preoral organ a putative homolog of the vertebrate Adenohypophysis
Brain Research Bulletin, 2008Co-Authors: Simona Candiani, Nicholas D Holland, Diana Oliveri, Manuela Parodi, Mario PestarinoAbstract:For the Florida amphioxus (Branchiostoma floridae), the full-length sequence and developmental expression of AmphiPOU1F1/Pit-1 are described. This gene, which is present in a single copy in the genome, is homologous to Pit-1 genes of vertebrates that play key roles in the development of the Adenohypophysis. During amphioxus development, AmphiPOU1F1/Pit-1 transcripts are limited to Hatschek's left diverticulum and the larval tissue developing from it--namely the concave portion of the preoral organ. No other expression domains for this gene were detected during embryonic and larval development. From data currently available for hemichordates, amphioxus and ascidians, the best supported homologs for the vertebrate Adenohypophysis are the preoral ciliary organ of hemichordates, preoral organ/Hatschek's pit of amphioxus and the neural gland/duct complex of ascidians. Better insights into pituitary evolution will require additional information: for invertebrate deuterostomes, more of the key pituitary genes in hemichordates and tunicates need to be studied; for the more basal groups vertebrates, it will be important to determine whether the source of the Adenohypophysis is endodermal or ectodermal and to demonstrate what, if any, contribution mesodermal head coeloms might make to the developing pituitary.