ZFIN ID: ZDB-PUB-090914-44
Characterization and Expression of the Nuclear Progestin Receptor in Zebrafish Gonads and Brain
Hanna, R.N., Daly, S.C., Pang, Y., Anglade, I., Kah, O., Thomas, P., and Zhu, Y.
Date: 2010
Source: Biology of reproduction   82(1): 112-122 (Journal)
Registered Authors: Kah, Olivier, Zhu, Yong
Keywords: Ovary, Testis, Hypothalamus, Progesterone, Progesterone receptor
MeSH Terms:
  • Amino Acid Sequence
  • Animals
  • Blotting, Western
  • Cell Proliferation
  • DNA Primers
  • Female
  • Hydroxyprogesterones/metabolism
  • Immunohistochemistry
  • Male
  • Molecular Sequence Data
  • Oocytes/metabolism*
  • Preoptic Area/metabolism*
  • Receptors, Progesterone/genetics
  • Receptors, Progesterone/metabolism*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Analysis, DNA
  • Testis/metabolism*
  • Zebrafish/metabolism*
PubMed: 19741205 Full text @ Biol. Reprod.
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ABSTRACT
The zebrafish nuclear progestin receptor (nPR, official symbol PGR) was identified and characterized in order to better understand its role in regulating reproduction in this well established teleost model. A full-length cDNA was identified that encoded a 618 amino acid residue protein with high homology to PGRs in other vertebrates, and contained the 5 domains characteristic of nuclear steroid receptors. In contrast to the multiplicity of steroid receptors often found in euteleosts and attributed to probable genome duplication, only a single locus encoding the full-length zebrafish pgr was identified. Cytosolic proteins from pgr-transfected cells showed a high affinity (Kd = 2 nM), saturable, single-binding site specific for a native progestin in euteleosts, 4-pregnen-17,20beta-diol-3-one (17,20beta-DHP). Both 17,20beta-DHP and progesterone (P4), were potent inducers of transcriptional activity in cells transiently transfected with pgr in a dual luciferase reporter assay, whereas androgens and estrogens had little potency. The pgr transcript and protein were abundant in the ovaries, testis and brain, and scarce or undetectable in the intestine, muscle and gills. Further analyses indicate that Pgr was expressed robustly in the preoptic region of the hypothalamus in the brain; proliferating spermatogonia and early spermatocytes in the testis; and in follicular cells and early stage oocytes (stage I and II), with very low levels within maturationally competent late stage oocytes (IV) in the ovary. The localization of Pgr suggests that it mediates progestin regulation of reproductive signaling in the brain, early germ cell proliferation in testis, and ovarian follicular functions, but not final oocyte or sperm maturation.
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