Abstract:

【Objective】 In order to reveal the apparent genetic mechanism of cattle-yaks about male sterile, DMR of SNRPN methylation status and its mRNA expression in testes between cattle-yaks and their parents were studied. 【Method】 The 5′-flanking sequence of SNRPN in yak was cloned and sequenced by the primers which designed on the basis of sequence of cattle SNRPN DNA. In cattle-yaks and their parents’ testes, the methylation status of SNRPN 5′-flanking was detected using sodium bisulfite sequencing and the SNRPN mRNA expression levels were also detected by Real-time PCR. 【Result】 The 5′-flanking sequence of SNRPN (1 137 bp) in yak was obtained, which the homology between yaks and cattle was 98.2%, and bioinformatics analysis suggested that the region contains the putative methylation-sensitive binding sites YY1 and SP1. The results showed that the methylation level of SNRPN gene in cattle-yaks (42.22%) was very significantly greater than that in cattle (21.08%) and yaks (20.81%) (P<0.01). The SNRPN expression level of cattle-yaks was lower than that of their parents in testes, but there was no significant difference (P>0.05). 【Conclusion】 The testicular methylation level of SNRPN gene in cattle-yaks was very significantly greater than that in cattle and yaks, the testicular SNRPN expression level of cattle-yaks was lower than that of their parents, indicating that the SNRPN gene maybe arrest meiotic process of spermatogenesis by its mRNA expression inhibition through the high methylation level of SNRPN gene DMR in cattle-yaks.

Key words: cattle-yak, SNRPN gene, methylation status, expression