Performing Department
School of Animal Science
Non Technical Summary
Brahman is a very popular cattle breed in the southern US. However, the beef produced by Brahman cattle is generally tough because of the low marbling level. Up to now, the underlying mechanism is still unclear. We recently found that a group of cells named fibro/adipogenic progenitors (FAPs) in cattle skeletal muscle can become both adipocytes (marbling fat) and cells that produce connective tissue. We hypothesize that the difference in quality between beef produced by Wagyu cattle, a breed producing highly marbled beef, and Brahman beef is due to their differences in FAPs. In Aim #1, gene expression of FAPs in the two cattle breeds at different growth and developmental stages will be studied at single-cell level. In Aim #2, the epigenetic mechanisms responsible for the differential gene expression between FAPs of the two breeds will be explored through genome-wide DNA methylation and chromatin accessibility analyses. In Aim #3, Wagyu x Brahman crossbreeding experiment will be conducted to evaluate the beef quality of crossbred cattle. We expect to reveal the mechanism through which FAPs regulate beef quality. The proposed study will suggest the use of FAP gene expression and epigenetic signatures in marker-assisted animal selection and demonstrate a new beef quality improvement strategy.
Animal Health Component
100%
Research Effort Categories
Basic
75%
Applied
25%
Developmental
(N/A)
Goals / Objectives
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 RNA sequencing (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).
Project Methods
In Aim #1, gene expression of fibro/adipogenic progenitors (FAPs) in Wagyu and Brahman cattle will be analyzed at single-celllevel at different cattle development and growth stages to study the differential lineage commitment and differentiation of FAPs in the two breeds of cattle. In Aim #2, DNA methylome andchromatin accessibility ofWagyu and Brahman FAPs will be studied byWhole-Genome Bisulfite Sequencing (WGBS) and Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq), respectively.In Aim #3, FAP gene expression,DNA methylome,andchromatin accessibilityof Wagyu-Brahman crossbred cattle will be compared with purebred cattle. Beef quality comparison will also be performed.