Putative regulatory factors associated with intramuscular fat content

Area of Science:

• Genetics and genomics
• Animal science
• Nutritional science

Background:

• Intramuscular fat (IMF) content impacts human health (insulin resistance, cardiovascular disease, obesity, type 2 diabetes) and meat quality.
• IMF deposition is influenced by genetics, sex, age, and nutrition.
• Understanding IMF molecular mechanisms is crucial for both human health and the beef industry.

Purpose of the Study:

• To investigate the molecular mechanisms underlying intramuscular fat content in Nellore steers.
• To identify differentially expressed genes (DEGs), biological pathways, and regulatory factors associated with extreme genomic estimated breeding values (GEBV) for IMF.
• To provide insights for improving beef production and nutritional value.

Main Methods:

• RNA-sequencing (RNA-seq) analysis of high (H) and low (L) GEBV groups.
• Gene set enrichment analysis (GSEA) and co-expression network analyses (PCIT, RIF, PIF).
• Pathway analysis using Pathway Studio software.

Main Results:

• Identified 77 differentially expressed genes (DEGs) between high and low IMF groups (FDR 10%).
• Discovered 13 significantly over-represented biological pathways and signaling pathways.
• Identified candidate regulatory genes (e.g., ANKRD26, HOXC5, PPAPDC2, GLI2, IGF2, MPC1, UBL5) and small RNAs (e.g., miR-1281).

Conclusions:

• The study elucidates molecular mechanisms of intramuscular adipogenesis and energy balance in muscle.
• Identified key genetic factors influencing IMF content in cattle.
• Findings support the development of healthier beef with improved nutritional profiles.