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Adenohypophysis
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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control of zebrafish pituitary development, with special focus on most recent findings, including some thus far unpublished data from our own laboratory on the transcription factor Six1.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.
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.
-
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.
-
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.