State Key Laboratory of Animal Biotech Breeding and Frontier Science Center for Molecular Design Breeding, China Agricultural University, Beijing, 100193, China; National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Department of Animal Genetics and Breeding, College of Animal Science and Technology China Agricultural University, Beijing 100193, China.
State Key Laboratory of Animal Biotech Breeding and Frontier Science Center for Molecular Design Breeding, China Agricultural University, Beijing, 100193, China; National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, Department of Animal Genetics and Breeding, College of Animal Science and Technology China Agricultural University, Beijing 100193, China; Sanya Institute of China Agricultural University, Hainan 572025, China.
Poult Sci. 2024 Aug;103(8):103882. doi: 10.1016/j.psj.2024.103882. Epub 2024 May 23.
Long-term intensive genetic selection has led to significant differences between broiler and layer chickens, which are evident during the embryonic period. Despite this, there is a paucity of research on the genetic regulation of the initial formation of muscle fiber morphology in chick embryos. Embryonic d 17 (E17) is the key time point for myoblast fusion completion and muscle fiber morphology formation in chickens. This study aimed to explore the genetic regulatory mechanisms underlying the early muscle fiber morphology establishment in broiler chickens of Cornish (CC) and White Plymouth Rock (RR) and layer chickens of White Leghorn (WW) at E17 using the transcriptomic and chromatin accessibility sequencing of pectoral major muscles. The results showed that broiler chickens exhibited significant higher embryo weight and pectoral major muscle weight at E17 compared to layer chickens (P = 0.000). A total of 1,278, 1,248, and 892 differentially expressed genes (DEGs) of RNA-seq data were identified between CC vs. WW, RR vs. WW, and CC vs. RR, separately. All DEGs were combined for cluster analysis and they were divided into 6 clusters, including cluster 1 with higher expression in broilers and cluster 6 with higher expression in layers. DEGs in cluster 1 were enriched in terms related to macrophage activation (P = 0.002) and defense response to bacteria (P = 0.002), while DEGs in cluster 6 showed enrichment in protein-DNA complex (P = 0.003) and monooxygenase activity (P = 0.000). ATAC-seq data analysis identified a total of 38,603 peaks, with 13,051 peaks for CC, 18,780 peaks for RR, and 6,772 peaks for WW. Integrative analysis of transcriptomic and chromatin accessibility data revealed GOLM1, ISLR2, and TOPAZ1 were commonly upregulated genes in CC and RR. Furthermore, screening of all upregulated DEGs in cluster 1 from CC and RR identified GOLM1, ISLR2, and HNMT genes associated with neuroimmune functions and MYOM3 linked to muscle morphology development, showing significantly elevated expression in broiler chickens compared to layer chickens. These findings suggest active neural system connectivity during the initial formation of muscle fiber morphology in embryonic period, highlighting the early interaction between muscle fiber formation morphology and the nervous system. This study provides novel insights into late chick embryo development and lays a deeper foundation for further research.
长期的密集遗传选择导致了肉鸡和蛋鸡之间的显著差异，这些差异在胚胎期就已经显现出来。尽管如此，关于鸡胚中肌肉纤维形态最初形成的遗传调控的研究仍然很少。胚胎 d17（E17）是鸡胚中成肌细胞融合完成和肌肉纤维形态形成的关键时间点。本研究旨在使用 Cornish（CC）和 White Plymouth Rock（RR）肉鸡以及 White Leghorn（WW）蛋鸡的胸大肌转录组和染色质可及性测序，探讨 E17 时肉鸡和蛋鸡早期肌肉纤维形态建立的遗传调控机制。结果表明，E17 时肉鸡胚胎体重和胸大肌重量显著高于蛋鸡（P = 0.000）。分别在 CC 与 WW、RR 与 WW 和 CC 与 RR 之间，RNA-seq 数据鉴定出 1278、1248 和 892 个差异表达基因（DEGs）。将所有 DEGs 进行聚类分析，将它们分为 6 个簇，包括簇 1 中在肉鸡中表达较高，簇 6 中在蛋鸡中表达较高。簇 1 中的 DEGs 富集在与巨噬细胞激活（P = 0.002）和细菌防御反应（P = 0.002）相关的术语中，而簇 6 中的 DEGs 显示在蛋白质-DNA 复合物（P = 0.003）和单加氧酶活性（P = 0.000）方面的富集。ATAC-seq 数据分析共鉴定出 38603 个峰，其中 CC 有 13051 个峰，RR 有 18780 个峰，WW 有 6772 个峰。转录组和染色质可及性数据的综合分析表明，GOLM1、ISLR2 和 TOPAZ1 是 CC 和 RR 中共同上调的基因。此外，从 CC 和 RR 中筛选簇 1 中所有上调的 DEGs，鉴定出与神经免疫功能相关的 GOLM1、ISLR2 和 HNMT 基因，以及与肌肉形态发育相关的 MYOM3 基因，在肉鸡中表达明显高于蛋鸡。这些发现表明在胚胎期肌肉纤维形态的最初形成过程中存在活跃的神经系统连接，突出了肌肉纤维形态形成与神经系统之间的早期相互作用。本研究为后期鸡胚发育提供了新的见解，并为进一步研究奠定了更深的基础。
