The Research Institute of Qinghai-Tibet Plateau, Southwest Minzu University, Chengdu, China.
Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Conservation and Exploitation, State Ethnic Affairs Commission and Ministry of Education, Chengdu, China.
J Dairy Res. 2020 May;87(2):158-165. doi: 10.1017/S0022029919001006. Epub 2020 Mar 19.
Yaks (Bos grunniens) live primarily in the Qinghai-Tibetan plateau (altitude: 2000-5000 m). Their milk presents unusual characteristics, containing large amounts of solids including fat and protein, and it is, therefore, important to understand the genetic makeup of the yak. To identify potentially critical genes playing a role in yak mammary tissue from colostrum to mature milk phase of lactogenesis, the early lactation (colostrum) stage (ELS; day 1 after parturition) and mature lactation (milk) stage (MLS; day 15) were chosen for comparison. An ELS-specific cDNA library was established by suppression subtractive hybridization and 25 expressed sequence tags at ELS were identified by sequencing and alignment. To further confirm our results the expression levels of 21 genes during the lactation cycle were measured using quantitative real-time RT-PCR (qRT-PCR). The qRT-PCR results confirmed 9 significantly up-regulated genes at ELS vs. MLS in yak mammary tissue, in which the l-amino acid oxidase 1 (LAO1) and collagen, type I, alpha I (COL1A1) were the most significantly up-regulated. During the lactation cycle, the highest expression of some milk fat genes (i.e., XDH and FABP3) in yak mammary tissue appears earlier than that in dairy cow. Our data also indicate MYC potentially playing a central role through putative regulation of COL1A1, CD44, SPARC, FASN and GPAM.
牦牛（Bos grunniens）主要生活在青藏高原（海拔：2000-5000 米）。它们的牛奶具有不同寻常的特性，含有大量的固体物质，包括脂肪和蛋白质，因此了解牦牛的基因构成非常重要。为了鉴定在牦牛乳腺组织从初乳到成熟乳阶段乳糖生成过程中可能起关键作用的潜在关键基因，选择早期泌乳（初乳）阶段（ELS；分娩后第 1 天）和成熟泌乳（乳汁）阶段（MLS；第 15 天）进行比较。通过抑制性消减杂交建立了 ELS 特异性 cDNA 文库，并通过测序和比对鉴定了 25 个 ELS 表达序列标签。为了进一步证实我们的结果，使用定量实时 RT-PCR（qRT-PCR）测量了泌乳周期中 21 个基因的表达水平。qRT-PCR 结果证实了 9 个在 ELS 与 MLS 之间在牦牛乳腺组织中显著上调的基因，其中 l-氨基酸氧化酶 1（LAO1）和胶原，I 型，α 1（COL1A1）是上调最显著的。在泌乳周期中，一些乳脂基因（即 XDH 和 FABP3）在牦牛乳腺组织中的表达高峰出现得比奶牛更早。我们的数据还表明，MYC 通过对 COL1A1、CD44、SPARC、FASN 和 GPAM 的潜在调节，可能发挥核心作用。
