[Differences in human and rat FSH receptors promote activity as a result of the transcriptional factors: E2F1, E2F4 and E2F5 overexpression].
FSH-R expression in granulosa cells varies during the course of ovarian ontogenesis, as well as, during each menstrual cycle. Expression of follicle-stimulating hormone receptors (FSH-R) on Sertoli cells of the testis and ovarian granulosa cells depend on many paracrine and autocrine factors. The modulation of FSH-R synthesis is accomplished via a number of mechanisms including regulation of the promoter activity. Little is known about factors involved in control of FSH-R transcription in different species. The aim of the present study was to investigate differences in the regulation of human and rat FSH-R promoter activity by E2F transcriptional factors.


METHODS
The 5'-flanking regions of human and rat FSH receptor gene subcloned in the pGL3 plasmid were transiently transfected into cultured CHO cells and rat granulosa cells. Rat granulosa cells were obtained by puncturing ovaries from DES primed immature Sprague-Dawley rats. Promoter activity was determined by measuring firefly luciferase luminescence of the cell lysate. Transfection efficiency was normalized by the renilla luciferase activity generated by co-transfected pRL-CMV vector. In order to determine the influence of E2F1, E2F4 and E2F5, on FSH-R promoter activity, cells were transfected either with promoter construct alone or with its mixture with selected expression vector.


RESULTS
Rat FSH-R promoter construct (-1033/+6 bp) and human FSH-R promoter construct (-1485/-1 bp) were both active in transfected cells. Overexpression of E2F1 protein decreased both, human and rat wild type FSH-R promoter activity. Overexpression of E2F4 did not affect neither rat nor human FSH-R gene transcription. Expression vector for E2F5 increased both, human and rat, FSH-R promoter activity. Folds of increase were markedly higher in case of rat FSH-R construct transfection, comparing to human FSH-R promoter.


CONCLUSIONS
Results suggest, that the E2F1 and E2F5 factors might play an opposite role in the regulation of FSH-R promoter activity. More pronounced stimulatory effect of E2F5 on the rat FSH-R can be explained by the presence of E2F site in the promoter. Since there is no E2F sensitive element in the human FSH-R promoter sequence, E2F1 and E2F5 can also indirectly influence FSH-R promoter activity.
Putowski
L
L
II Katedry i Kliniki Ginekologii Operacyjnej Akademii Medycznej w Lublinie.
Gasior
W
W
Gogacz
M
M
Gagała
J
J
Jakowicki
J A
JA
D000818:Animals; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D050704:E2F4 Transcription Factor; D050700:E2F5 Transcription Factor; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics; D006107:Granulosa Cells / Q000378:metabolism; D006801:Humans; D008297:Male; D011401:Promoter Regions, Genetic / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D011962:Receptors, FSH / Q000235:genetics / Q000378:metabolism*; D012708:Sertoli Cells / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D050704:E2F4 Transcription Factor; C493762:E2F4 protein, human; D050700:E2F5 Transcription Factor; C092558:E2F5 protein, human; C493755:E2f1 protein, rat; C490489:E2f5 protein, rat; D011962:Receptors, FSH; D014157:Transcription Factors