Génétique Animale et Biologie Intégrative, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France; Animal Breeding and Genomics, Wageningen University and Research, PO Box 338, 6700 AH Wageningen, the Netherlands.
Animal Breeding and Genomics, Wageningen University and Research, PO Box 338, 6700 AH Wageningen, the Netherlands.
J Dairy Sci. 2019 Feb;102(2):1374-1385. doi: 10.3168/jds.2018-15593. Epub 2018 Dec 20.
Phosphorylation of caseins (CN) is a crucial post-translational modification that allows caseins to form colloid particles known as casein micelles. Both α- and α-CN show varying degrees of phosphorylation (isoforms) in cow milk and were suggested to be more relevant for stabilizing internal micellar structure than β- and κ-CN. However, little is known about the genetic background of individual α-CN phosphorylation isoforms and the phosphorylation degrees of α- and α-CN (α-CN PD and α-CN PD), defined as the proportion of isoforms with higher degrees of phosphorylation in total α- and α-CN, respectively. We aimed to identify genomic regions associated with these traits using 50K single nucleotide polymorphisms for 1,857 Dutch Holstein Friesian cows. A total of 10 quantitative trait loci (QTL) regions were identified for all studied traits on 10 Bos taurus autosomes (BTA1, 2, 6, 9, 11, 14, 15, 18, 24, and 28). Regions associated with multiple traits were found on BTA1, 6, 11, and 14. We showed 2 QTL regions on BTA1, one affecting α-CN production and the other harboring the SLC37A1 gene, which encodes a phosphorus antiporter and affects α- and α-CN PD. The QTL on BTA6 harbors the casein gene cluster and affects individual α-CN phosphorylation isoforms. The QTL on BTA11 harbors the PAEP gene that encodes for β-lactoglobulin and affects relative concentrations of α-CN-10P and α-CN-11P as well as α-CN PD and α-CN PD. The QTL on BTA14 harbors the DGAT1 gene and affects relative concentrations of α-CN-10P and α-CN-11P as well as α-CN PD and α-CN PD. Our results suggest that effects of identified genomic regions on phosphorylation of α- and α-CN are related to changes in milk synthesis and phosphorus secretion in milk. The actual roles of SLC37A1, PAEP, and DGAT1 in α- and α-CN phosphorylation in Dutch Holstein Friesian require further investigation.
酪蛋白（CN）的磷酸化是一种至关重要的翻译后修饰，使酪蛋白能够形成胶体颗粒，称为酪蛋白胶束。牛乳中的α-CN 和 α-CN 都表现出不同程度的磷酸化（同工型），并被认为比β-CN 和 κ-CN 更能稳定内部胶束结构。然而，关于个体α-CN 磷酸化同工型的遗传背景以及α-CN 和 α-CN 的磷酸化程度（α-CN PD 和 α-CN PD），即同工型中具有更高磷酸化程度的比例分别在总α-CN 和α-CN 中的定义，知之甚少。我们旨在使用 50K 单核苷酸多态性对 1857 头荷兰荷斯坦弗里生奶牛进行研究，以确定与这些性状相关的基因组区域。总共在 10 个牛 Taurus 染色体（BTA1、2、6、9、11、14、15、18、24 和 28）上鉴定出 10 个与所有研究性状相关的数量性状基因座（QTL）区域。在 BTA1、6、11 和 14 上发现了与多个性状相关的区域。我们在 BTA1 上显示了 2 个 QTL 区域，一个影响α-CN 的产生，另一个包含 SLC37A1 基因，该基因编码磷反向转运蛋白，影响α-CN 和α-CN PD。BTA6 上的 QTL 包含酪蛋白基因簇，影响个体α-CN 磷酸化同工型。BTA11 上的 QTL 包含编码β-乳球蛋白的 PAEP 基因，影响α-CN-10P 和α-CN-11P 的相对浓度以及α-CN PD 和α-CN PD。BTA14 上的 QTL 包含 DGAT1 基因，影响α-CN-10P 和α-CN-11P 的相对浓度以及α-CN PD 和α-CN PD。我们的结果表明，鉴定的基因组区域对α-CN 和α-CN 磷酸化的影响与乳合成和乳中磷分泌的变化有关。SLC37A1、PAEP 和 DGAT1 在荷兰荷斯坦弗里生牛中α-CN 和α-CN 磷酸化中的实际作用需要进一步研究。
