INTRAMUSCULAR FAT OF CATTLE, ALSO KNOWN AS MARBLING, IS A KEY DETERMINANT OF BEEF QUALITY. THE AMOUNT OF INTRAMUSCULAR FAT IS POSITIVELY ASSOCIATED WITH THE PALATABILITY AND JUICINESS AND HENCE THE VALUE OF BEEF. COMPARED TO OUR KNOWLEDGE OF SUBCUTANEOUS OR VISCERAL FAT, WHICH IS CONSIDERED AS WASTE IN CATTLE, LITTLE IS KNOWN ABOUT THE CELLULAR AND MOLECULAR MECHANISMS THAT CONTROL THE FORMATION AND GROWTH OF INTRAMUSCULAR FAT. THE BOTTLENECK IN UNDERSTANDING THESE MECHANISMS IS THE IDENTITY AND ORIGIN OF THE PRECURSOR CELLS FOR INTRAMUSCULAR ADIPOCYTES, I.E., INTRAMUSCULAR PREADIPOCYTES. THE OVERALL GOAL OF THIS PROJECT IS, THEREFORE, TO IDENTIFY AND CHARACTERIZE THE INTRAMUSCULAR PREADIPOCYTES IN CATTLE. WE HYPOTHESIZE THAT BOVINE INTRAMUSCULAR PREADIPOCYTES HAVE UNIQUE MOLECULAR SIGNATURES AND THAT THEIR DIFFERENTIATION INTO ADIPOCYTES IS REGULATED BY UNIQUE MECHANISMS. WE WILL TEST THESE HYPOTHESES BY CONDUCTING THE FOLLOWING STUDIES: 1) IDENTIFY THE MOLECULAR SIGNATURES OF BOVINEINTRAMUSCULAR PREADIPOCYTES AND THEIR LOCATIONS AND DISTRIBUTION IN SKELETAL MUSCLE; 2) DETERMINE THE TRANSCRIPTIONAL MECHANISMS THAT REGULATE DIFFERENTIATION OF BOVINE INTRAMUSCULAR PREADIPOCYTES INTO MATURE ADIPOCYTES. THESE STUDIES WILL GENERATE NOVEL INSIGHTS INTO THE IDENTITY, LOCATION, AND REGULATION OF BOVINE INTRAMUSCULAR PREADIPOCYTES. THESE INSIGHTS WILL NOT ONLY FILL A GAP IN THE FUNDAMENTAL KNOWLEDGE OF BOVINE SKELETAL MUSCLE BIOLOGY BUT COULD ALSO BE USED TO DEVELOP STRATEGIES TO PRODUCE BETTER, TASTIER BEEF FOR THE CONSUMERS AND MORE PROFITS FOR THE PRODUCERS.