Heterogeneous nuclear ribonucleoprotein A/B and G inhibits the transcription of gonadotropin-releasing-hormone 1.
Gonadotropin-releasing hormone 1 (GnRH1) causes the release of gonadotropins from the pituitary to control reproduction. Here we report that two heterogeneous nuclear ribonucleoproteins (hnRNP-A/B and hnRNP-G) bind to the GnRH-I upstream promoter region in a cichlid fish Astatotilapia burtoni. We identified these binding proteins using a newly developed homology based method of mass spectrometric peptide mapping. We show that both hnRNP-A/B and hnRNP-G co-localize with GnRH1 in the pre-optic area of the hypothalamus in the brain. We also demonstrated that these ribonucleoproteins exhibit similar binding capacity in vivo, using immortalized mouse GT1-7 cells where overexpression of either hnRNP-A/B or hnRNP-G significantly down-regulates GnRH1 mRNA levels in GT1-7 cells, suggesting that both act as repressors in GnRH1 transcriptional regulation.
Zhao
Sheng
S
Department of Biological Sciences & Program in Neuroscience, Stanford University, Stanford, California 94305-5020, USA.
Korzan
Wayne J
WJ
Chen
Chun-Chun
CC
Fernald
Russell D
RD
D000818:Animals; D001665:Binding Sites / Q000502:physiology; D002461:Cell Line, Transformed; D023681:Cichlids; D003001:Cloning, Molecular; D005786:Gene Expression Regulation / Q000502:physiology*; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D034441:Heterogeneous-Nuclear Ribonucleoproteins / Q000145:classification* / Q000502:physiology*; D051379:Mice; D008969:Molecular Sequence Data; D010449:Peptide Mapping / Q000379:methods; D011401:Promoter Regions, Genetic / Q000502:physiology; D011485:Protein Binding / Q000502:physiology; D014162:Transfection / Q000379:methods
D034441:Heterogeneous-Nuclear Ribonucleoproteins; D007987:Gonadotropin-Releasing Hormone