Single nucleotide polymorphisms of follicle-stimulating hormone receptor promoter and their impacts to the promoter activities.

Women of reproductive ages are varies in their responses to exogenous FSH stimulations. The difference of FSHR genotype due to the polymorphisms in exon 10 is one of its significant factors. To know further whether the core promoter of FSHR is also polymorphic and to know whether those polymorphisms influence the promoter activity, we did polymorphism screening of FSHR promoter to 262 women undergoing IVF/ICSI, followed by functional study to know the impact of polymorphisms to the promoter activity. This study indicated that the core promoter of human FSHR is polymorphic. We found five SNPs at positions –29, –37, –114, –123 and –138 in addition to the variety number of adenines. Polymorphism at position –123 significantly decreased the promoter activity, in contrast, polymorphism at position –37 and –138 significantly increased the promoter activity, whereas polymorphism at position –29, –114 and short adenines stretch did not significantly influence the promoter activity. The differences of the promoter activities due to polymorphisms might change the ovarian sensitivity to FSH.

The expression of follicle-stimulating hormone receptor in ovary and testis.

Follicle-stimulating hormone receptor (FSHR) is exclusively expressed in granulose cells of the ovary and Sertoli cells of the testis. The highly cell-specific of gene expression revealed that transcriptional events unique to these two cell types are responsible for activation of the FSHR gene. Even though its mechanisms are still unclear, several progress regarding the mechanism that control its basal transcription and regulation has been made. It has been identified several important elements that responsible for the transcription of the TATA-less FSHR gene such as: E box element (CACG(A)TG, –124/–119), an inverted GATA (TATC, –88/–85), E2F (TTTCGCG, –45/–39), and regulator element-3 (–197/–171). The functional studies shown that mutations through these regulatory elements significantly decrease the promoter function with greatest impact detected when mutation was done in E-box element. The site-specific CpG methylation within the core promoter seems play an important role in the regulation of rat and mouse FSHR gene expression.