Regulation of ribonuclease expression by estradiol in Rana catesbeiana (Bullfrog).
Multiple ribonucleases are widely found in living organisms, but the function and regulation of individual ribonucleases are still not clear. In the present study, we found that one oocytic ribonuclease, RC-RNase, is developmentally expressed in the liver and stored in the oocyte of the bullfrog, while another ribonuclease, RC-RNase L1, is constitutively expressed and retained in the liver at all stages. In females, the expression of RC-RNase increased with the degree of maturity and the concentration of plasma estradiol during oogenesis. In males, the RC-RNase gene was activated in the liver and the newly synthesized protein was secreted into plasma if estradiol was administered. To investigate the mechanism of estrogen-mediated activation of ribonuclease expression, we cloned the RC-RNase promoter and analyzed the putative transcription factor binding sites, e.g. TATA box, ERE, AP1 and CAAT box. Using luciferase as a reporter gene, we found that an estrogen response element in the promoter of RC-RNase was essential for both basic transcription and estradiol-mediated gene activation in estrogen receptor-positive MCF7 cells. These results support the hypothesis that RC-RNase is synthesized in the liver upon stimulation by estradiol during oogenesis, then secreted into the bloodstream and stored in oocytes for embryonic development.
Tang
Pin-Chi
PC
Institute of Biomedical Sciences, Academia Sinica, 128, Yen-Chiu-Yuan Road, Sec. 2, Taipei 115, Taiwan.
Huang
Huey-Chung
HC
Wang
Sui-Chi
SC
Jeng
Jen-Chong
JC
Liao
You-Di
YD
D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D008099:Liver / Q000201:enzymology; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics; D012313:RNA / Q000378:metabolism; D011898:Ranidae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012260:Ribonucleases / Q000097:blood / Q000235:genetics* / Q000378:metabolism; D013997:Time Factors; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured
D011993:Recombinant Fusion Proteins; D004958:Estradiol; D012313:RNA; D008156:Luciferases; D012260:Ribonucleases