Β-microseminoprotein(msmb) is one of the most abundant proteins in human seminal plasma. this protein binds to head and neck of sperm and inhibits spontaneous acrosome reaction. msmb gene has 4 exons that exon 2 and 4 code the region that binds to crisp-3. it is involved in sperm-zona pellucida interaction. we assumed that mutation in this region can disrupt the binding of the two proteins, therefore, interfere in the interaction of sperm-zona pellucida. accordingly, the association between the genetic variations in functional domains coding regions of msmb gene in infertile men with unexplained infertility was evaluated.
Methods
In this study 73 unexplained infertile men as case group and 70 fertile men as control group were included. genomic alteration was assessed using pcr-sequencing. statistical analysis was done using chi square (p<0.05).
Results
No alterations were observed in exon 2 and 4 of msmb gene. an intronic variant(rs2075894) was found downstream of exon 2 with a significant difference(p-value <.05) in genotypic frequency between the control and patient groups. this variant is the binding site of 5 transcription factors(gata2, gata3, freac-4, ying-yang, mzf_1-4), but none of these was not specific to testicular tissue. also, this variant is the binding site of two splicing factors(hnrnp h1, hnrnp h2), but further research on the "human splicing finder" reveals that it has no effect on the splicing process
Conclusion
Msmb gene may not be associated with infertility in unexplained men infertility. of course these results may be due to the small number of samples.
