National Engineering Laboratory for Animal Breeding, Beijing Key Laboratory for Animal Genetic Improvement, College of Animal Science and Technology, China Agricultural University, Beijing, China.
Sci Rep. 2020 Jul 8;10(1):11213. doi: 10.1038/s41598-020-68178-w.
The Tibetan chicken is a unique breed that has adapted to the high-altitude hypoxic conditions of the Tibetan plateau. A number of positively selected genes have been reported in these chickens; however, the mechanisms of gene expression for hypoxia adaptation are not fully understood. In the present study, eggs from Tibetan and Chahua chickens were incubated under hypoxic and normoxic conditions, and vascularization in the chorioallantoic membrane (CAM) of embryos was observed. We found that the vessel density index in the CAM of Tibetan chickens was lower than in Chahua chickens under hypoxia conditions. Transcriptomic and proteomic analyses of CAM tissues were performed in Tibetan and Chahua chicken embryos under hypoxic incubation using RNA-Seq and iTRAQ. We obtained 160 differentially expressed genes and 387 differentially expressed proteins that were mainly enriched in angiogenesis, vasculature development, blood vessel morphogenesis, blood circulation, renin-angiotensin system, and HIF-1 and VEGF signaling pathways. Twenty-six genes involved in angiogenesis and blood circulation, two genes involved in ion transport, and six genes that regulated energy metabolism were identified as candidate functional genes in regulating hypoxic adaptation of chicken embryos. This research provided insights into the molecular mechanism of hypoxia adaptation in Tibetan chickens.
藏鸡是一种适应青藏高原高海拔低氧环境的独特品种。研究已经报道了这些鸡种中存在一些正选择的基因，但对于低氧适应的基因表达机制尚不完全清楚。本研究在低氧和常氧条件下孵化藏鸡和茶花鸡的鸡蛋，并观察胚胎绒毛尿囊膜（CAM）的血管生成情况。我们发现，在低氧条件下，藏鸡 CAM 的血管密度指数低于茶花鸡。使用 RNA-Seq 和 iTRAQ 对低氧孵育条件下的藏鸡和茶花鸡胚胎的 CAM 组织进行了转录组和蛋白质组分析。我们获得了 160 个差异表达基因和 387 个差异表达蛋白，这些基因和蛋白主要富集在血管生成、血管发育、血管形态发生、血液循环、肾素-血管紧张素系统以及 HIF-1 和 VEGF 信号通路。鉴定出 26 个与血管生成和血液循环相关的候选功能基因、2 个与离子转运相关的基因以及 6 个调节能量代谢的基因，它们可能在调控鸡胚胎的低氧适应中发挥作用。本研究为藏鸡的低氧适应分子机制提供了新的见解。
