BACKGROUND: Vasa is a member of the DEAD-box protein family that plays an 
indispensable role in mammalian spermatogenesis, particularly during meiosis. 
Bovine vasa homology (Bvh) of Bos taurus has been reported, however, its 
function in bovine testicular tissue remains obscure. This study aimed to reveal 
the functions of Bvh and to determine whether Bvh is a candidate gene in the 
regulation of spermatogenesis in bovine, and to illustrate whether its 
transcription is regulated by alternative splicing and DNA methylation.
RESULTS: Here we report the molecular characterization, alternative splicing 
pattern, expression and promoter methylation status of Bvh. The full-length 
coding region of Bvh was 2190 bp, which encodes a 729 amino acid (aa) protein 
containing nine consensus regions of the DEAD box protein family. Bvh is 
expressed only in the ovary and testis of adult cattle. Two splice variants were 
identified and termed Bvh-V4 (2112 bp and 703 aa) and Bvh-V45 (2040 bp and 679 
aa). In male cattle, full-length Bvh (Bvh-FL), Bvh-V4 and Bvh-V45 are 
exclusively expressed in the testes in the ratio of 2.2:1.6:1, respectively. 
Real-time PCR revealed significantly reduced mRNA expression of Bvh-FL, Bvh-V4 
and Bvh-V45 in testes of cattle-yak hybrids, with meiotic arrest compared with 
cattle and yaks with normal spermatogenesis (P < 0.01). The promoter methylation 
level of Bvh in the testes of cattle-yak hybrids was significantly greater than 
in cattle and yaks (P < 0.01).
CONCLUSION: In the present study, Bvh was isolated and characterized. These data 
suggest that Bvh functions in bovine spermatogenesis, and that transcription of 
the gene in testes were regulated by alternative splice and promoter 
methylation.