Tao Ren

CaMK4, a calcium/calmodulin-dependent protein kinase, is an important mediator of cellular signal transduction, yet its role in the regulation of skeletal muscle satellite cells (MuSCs) in goats has remained unclear. In this study, CaMK4 overexpression and knockdown models were established, and integrated transcriptomic and proteomic analyses were performed to systematically elucidate its regulatory network. CaMK4 overexpression altered key pathways associated with cell proliferation and muscle development, including cAMP, PI3K-Akt, and actin cytoskeleton regulation, while proteomic data highlighted calcium signaling and JAK-STAT pathways. Conversely, CaMK4 knockdown enhanced MuSC proliferation by upregulating cell cycle-related genes and proteins. Integrated analyses further identified that Galectin-9 (LGALS9), Collagen triple helix repeat containing-1 (CTHRC1), Hyaluronan Synthase 1 (HAS1), and L-Threonine Dehydrogenase (TDH) may serve as potential key nodes regulating cell cycle, apoptosis, and metabolic control. This suggests a regulatory role for CaMK4. Collectively, these findings provide a mechanistic framework for understanding CaMK4 function in ruminant muscle development and may offer insights for improving goat muscle growth, meat quality traits, and production efficiency.

Growth traits are among the most important economic phenotypes targeted in the genetic improvement of beef cattle. To understand the genetic basis of growth traits in Huaxi cattle, we performed a genome-wide association study (GWAS) on body weight, eye muscle area, and back fat thickness across five developmental stages in a population of 202 Huaxi cattle. Additionally, publicly available RNA-seq data from the longissimus dorsi muscle of both young and adult cattle were analyzed to identify key genes and genetic markers associated with growth in Huaxi cattle. In total, 7.19 million high-quality variant loci (SNPs and INDELs) were identified across all samples. In the GWAS, the three multilocus models (FarmCPU, MLMM, and BLINK) outperformed the conventional single-locus models (CMLM, GLM, and MLM). Consequently, GWAS analysis was conducted using multilocus models, which identified 99 variant loci significantly associated with growth traits and annotated a total of 83 candidate genes (CDGs). Additionally, 23 of the 83 CDGs overlapped with significantly differentially expressed genes identified from public RNA-seq datasets of longissimus dorsi muscle between young and adult cattle. Furthermore, gene functional enrichment (KEGG and GO) analyses revealed that over 30% of the pathways and GO terms were associated with muscle development and fat deposition, crucial factors for beef production. Specifically, key genes identified included MGLL, SGMS1, SNX29 and AKAP6, which are implicated in lipid metabolism, adipogenesis, and muscle growth. In summary, this study provides new insights into the genetic mechanisms underlying growth traits in Huaxi cattle and presents promising markers for future breeding improvements.