Leibniz Institute for Farm Animal Biology, Research Unit Molecular Biology, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany.
J Anim Sci. 2012 Jan;90(1):1-15. doi: 10.2527/jas.2011-4269. Epub 2011 Aug 19.
The inverted teat defect is characterized by the failure of teats to protrude from the udder surface and has a negative effect on the economic efficiency of pig production. The inverted teat defect is influenced by genetic factors, but the number and identity of relevant genes are unknown. In this study, we compared the mRNA expression of teat tissues from unaffected pigs and affected pigs by using microarrays. Simultaneously, 24,123 probe sets were screened, of which some 15,000 had present calls and were analyzed for differential expression between mesenchymal and epithelial tissue of 3 categories of teats (i.e., normal teats of unaffected and affected animals, and inverted teats of the latter). Differential expression was more pronounced in epithelial than in mesenchymal tissue, and the comparisons among the 3 categories of teats showed that local processes at the side of the affected area as well as processes taking place at the level of the organ contribute to the development of inverted teats. Genes related to biofunctions of cell maintenance, proliferation, differentiation, and replacement; organismal, organ, and tissue development; genetic information and nucleic acid processing; and cell-to-cell signaling and interaction were differentially expressed, depending on the teat phenotype and the status of the animal as affected or unaffected. In particular, genes encoding members of canonical pathways of growth factor signaling were highlighted. Complementary to previous real-time quantitative reverse-transcription PCR experiments showing upregulation of growth factors (epidermal growth factor, fibroblast growth factor, hepatocyte growth factor, platelet-derived growth factor, vascular endothelial growth factor) and their receptors in the inverted teat, here it is shown that the abundance of transcripts encoding subordinated proteins (acid phosphatase 1, soluble; activating transcription factor 2; casein kinase 2, α 1 polypeptide; casein kinase 2, α prime polypeptide; actinin, α 2; and Homo sapiens growth factor receptor-bound protein 2) within the growth factor signaling pathways are also affected. Tuning of the expression of genes of these pathways balances the differentiation and proliferation of epithelial and mesenchymal teat tissue and finally affects the shape and structure of the teats.
内陷乳头缺陷的特征是乳头未能从乳房表面突出，对猪生产的经济效益有负面影响。内陷乳头缺陷受遗传因素影响，但相关基因的数量和身份未知。在这项研究中，我们通过微阵列比较了正常和受影响的猪乳头组织的 mRNA 表达。同时，筛选了 24123 个探针集，其中约 15000 个有存在调用，并分析了 3 类乳头（即正常猪的正常乳头和受影响动物的正常乳头，以及后者的内陷乳头）的间充质和上皮组织之间的差异表达。上皮组织的差异表达比间充质组织更明显，而 3 类乳头之间的比较表明，受影响区域的侧方局部过程以及在器官水平发生的过程都有助于内陷乳头的发育。与细胞维持、增殖、分化和替代的生物功能相关的基因；生物体、器官和组织发育；遗传信息和核酸处理；以及细胞间信号转导和相互作用，根据乳头表型和动物的受影响或不受影响的状态而差异表达。特别是，编码经典生长因子信号通路成员的基因被突出显示。与以前显示在反转乳头中上调生长因子（表皮生长因子、成纤维细胞生长因子、肝细胞生长因子、血小板衍生生长因子、血管内皮生长因子）及其受体的实时定量逆转录 PCR 实验互补，这里表明转录本编码的亚基蛋白（酸性磷酸酶 1、可溶性；激活转录因子 2；酪蛋白激酶 2、α1 多肽；酪蛋白激酶 2、α 主要多肽；肌动蛋白、α2；和人生长因子受体结合蛋白 2）的丰度在生长因子信号通路中也受到影响。这些途径的基因表达的调节平衡了上皮和间充质乳头组织的分化和增殖，最终影响了乳头的形状和结构。
