FIBRO/ADIPOGENIC PROGENITORS AND BEEF QUALITY

Recent animal studies suggest that a group of resident bipotent progenitor cells named fibro/adipogenic progenitors (FAPs) are responsible for the formation of both intramuscular adipose tissue and connective tissue. A comprehensive screening for gene expression differences in FAPs between Brahman and Wagyu will provide a greater understanding of molecular factors influencing beef quality. The selection of a low-marbling breed (Brahman) and a high-marbling breed (Wagyu) in the proposed study will provide a unique model for successfully identifying the molecular markers for this valuable beef quality trait. Our long-term goal is to improve beef quality through manipulating the differentiation activity of FAPs. The central hypothesis of this proposed study is that the difference in lineage commitment and differentiation of FAP is a major factor contributing to the distinct qualities of Brahman and Wagyu beef. The objectives of this application are 1) to characterize the unique transcriptomic signatures during lineage commitment and differentiation of FAPs in Brahman and Wagyu cattle through single-cell RNAsequencing (scRNA-seq) analyses at different growth and developmental stages (Aim #1); 2) to explore the precise epigenetic machinery for gene regulation during lineage commitment and differentiation of FAPs in Brahman and Wagyu cattle using Whole-Genome Bisulfite Sequencing (WGBS) and Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq) (Aim #2); and 3) to evaluate the meat quality traits of Wagyu x Brahman crossbred cattle and the correlations between beef quality and identified FAP transcriptomic and epigenetic signatures, which will provide an efficient and feasible beef quality improvement strategy and suggest novel target genes and pathways for future beef quality improvement studies (Aim #3).