The Cloning And Quantitative Express Of BCMO1 And BCO2 Gene In Yak

Yak fat plays an important role in energy storage, organization protection, to maintain body temperature and fat soluble vitamin balance during the process of adapting to the alpine environment.In the lack of forage, yak can able to maintain vitamin A balance, which is directly related to accumulation of carotenoids in fat. Studies have shown that β-carotene enrichment in adipose tissue leads to yak yellow fat. It is interesting question whether is there special metabolic pathways of β-carotene metabolism in yak. Therefore, this paper selects the related enzyme genes involved in BCMO1 gene and BCO2 gene as the research object. The core sequence of BCMO1 and BCO2 were obtained using reverse transcription polymerase chain reaction, and the 3 ’end and 5’ end sequence was obtained using rapid amplification of cDNA ends. Using real-time fluorescence quantitative PCR to got the level of the mRNAs expression of BCMO1 and BCO2 in different yak tissues at the different nutrition periods. The results showed that BCMO1 gene sequence length is 1916 bp and the open reading frame length is 1644 bp, which encods 576 amino acids. It is also showed that BCO2 gene sequence length is 2043 bp and the open reading frame length is 1662 bp, which encods 553 amino acids. It was found that the non-coding region of BCMO1 contains TATA kit that correctly positioning the gene transcription by analysising the gene structure. The BCO2 have nonsense mutation in nucleotide sequence, so that the amino acid residues of encoding region has changed, whether it has led to the formation of yak yellow fat need to be further verified. Analysis of protein structure found that the two proteins have a conserved structure of the RPE65 superfamily. BCMO1 is a cytoplasmic protein, and BCO2 is a mitochondrial protein. The BCMO1 and BCO2 mRNA were expressed in duodenum, kidney, muscle, intestine, liver, ileum, lung, rumen tissues of yak during different nutrition period. The level of BCMO1 gene expression was highest in duodenum at both rich nutrition period and nutrition deficiency(P < 0.05), and it is the lowest in the lungs among all the tissues(P < 0.05). The BCO2 gene expression was the highest in duodenum(P < 0.05), and it’s the lowest in the rumen among all the tissues at nutrition deficiency period(P < 0.05). BCO2 mRNA expression was the highest in muscle(P < 0.05) at rich nutrition period,and in the lungs expression was the lowest(P < 0.05). The characteristies of special expression of BCMO1 gene and BCO2 is related to the level of β-carotene in the forage. And it may be play an important role in the regulation of vitamin metabolism and seasonal nutritional adaptation mechanism.