关键词: 牦牛, 乳腺, DBI, 克隆, 分子特征

Abstract: Diazepam binding inhibitor (DBI) has a high affinity with acyl-CoA and is widely expressed in animal tissues, which is closely related to fatty acid metabolism and steroid hormone synthesis. In order to study the molecular characteristics of DBI gene and its role in the development of mammary gland, the coding region of DBI gene in yaks was cloned and bioinformatics analysis was performed. Quantitative Real-time PCR (qPCR), Western blotting (WB) and Immuno-histochemistry (IHC) assays were used to explore the relative expression level and expression sites of DBI in the mammary tissues of yak in the early lactation, lactation, and dry milk periods. DBI sequence analysis showed that the coding region of yak DBI gene is 264 bp long, encoding 87 amino acids, and the homology with Bos taurus is 99. 62%. qPCR data showed that the relative expression level of DBI gene in the mammary tissue of yak in early lactation was significantly higher than during lactation and dry periods (P< 0. 05). WB results showed that the expression of DBI protein in the mammary tissue of yak was the highest in early lactation, followed by dry period, and the lowest in lactation (P< 0. 05). IHC results showed that there was no significant difference in the expression sites of DBI in different development stages of yak mammary gland, and it is mainly expressed in acinar epithelial cells, ductal epithelial cells, and lobular mesenchymal cells. There were significant differences in the relative expression levels of DBI in different development stages of yak mammary tissue (P< 0. 05), suggesting that DBI may be involved in the development of yak mammary gland, which provides a theoretical reference for further exploration of the role of DBI gene in the organism.

Key words: Yak, Mammary gland, Diazepam binding inhibitor (DBI), Cloning, Molecular characteristics