USF2 inhibits C/EBP-mediated transcriptional regulation of the RIIbeta subunit of cAMP-dependent protein kinase.
BMC Mol Biol 2002;
3:10. [PMID:
12086590 PMCID:
PMC117135 DOI:
10.1186/1471-2199-3-10]
[Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2002] [Accepted: 06/21/2002] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND
Cyclic AMP-dependent protein kinase (PKA) plays a central role in regulation of energy metabolism. Upon stimulation of testicular Sertoli cells by follicle stimulating hormone (FSH), glycolysis is activated to increase the production of nutrients for the germ cells, and a new regulatory subunit of cAMP-dependent protein kinase, RIIbeta, is induced. We have previously shown that production of the transcription factor C/EBPbeta is rapidly increased by FSH and cAMP in primary Sertoli cell cultures, and that C/EBPbeta induces the RIIbeta promoter.
RESULTS
In this work we show that USF1, USF2 and truncated USF isoforms bind to a conserved E-box in the RIIbeta gene. Interestingly, overexpression of USF2, but not USF1, led to inhibition of both cAMP- and C/EBPbeta-mediated induction of RIIbeta. Furthermore, Western blots show that a novel USF1 isoform is induced by cAMP in Sertoli cells.
CONCLUSIONS
These results indicate that the expression of various USF isoforms may be regulated by cAMP, and that the interplay between USF and C/EBPbeta is important for cAMP-mediated regulation of RIIbeta expression. The counteracting effects of USF2 and C/EBPbeta observed on the RIIbeta promoter is in accordance with the hypothesis that C/EBP and USF play opposite roles in regulation of glucose metabolism.
Collapse