Cloning and Expression Analysis of and in the Testes of Mature Yaks and Their Sterile Hybrids.

The objective of this study was to explore the molecular mechanism of male sterility in yak hybrids based on and . Total RNA was extracted from the testes of adult yaks ( = 11) and sterile cattle-yaks ( = 11) followed by reverse transcription. The coding sequence (CDS) of yak and were obtained by conventional polymerase chain reaction (PCR) and gene cloning. The testicular mRNA and protein levels of and in yaks and cattle-yaks were detected by quantitative PCR (qPCR) and Western blotting, respectively, and the histone H3 lysine 9 (H3K9) histone acetylation level in the testes of yaks and cattle-yaks was assayed using enzyme linked immunosorbent assay (ELISA). The results showed that the CDS of and were 1242 bp and 1449 bp in length, encoding 413 and 482 amino acids, respectively; yaks had a similar mRNA sequence as cattle in both genes. The testicular mRNA and protein levels of of cattle-yaks were significantly lower than those of yaks, and the protein level of was significantly higher than that of yaks. ELISA showed that the acetylation level of testicular H3K9 was significantly lower in yak hybrids than that of yaks. The present results suggest that the decreased level of and increased level of may result in the decreased H3K9 acetylation in cattle-yaks and might be associated with their sterility.