Abstract:

The study aims to understand the molecular function of fatty acid binding protein 4(FABP4)in Holstein cows and its expression pattern in different tissues.The coding sequence(CDS)of FABP4 gene was amplified by PCR using mammary tissue of Holstein cows as cDNA template,and bioinformatics analysis was performed.The qRT-PCR was used to detect the relative mRNA expression levels of FABP4 gene in small intestine,liver,mammary gland,heart,uterus,kidney and ovary tissues.The results showed that the sequence of the coding region of FABP4 gene in Holstein cows was 399 bp long,encoding 133 amino acids,and the secondary structure of the protein was mainly β-folded.The amino acid homology analysis revealed that bovine FABP4 was most closely related to sheep and goats;nucleoplasmic localization indicated that FABP4 gene might play an important function in the cytoplasm.Protein interaction analysis of FABP4 using STRING revealed that it was closely related to lipid-related proteins such as FABP3,PPARG,and LIPE.The qRT-PCR showed that FABP4 was expressed in all tissues of mid-lactation cows,but the highest expression was found in the mammary tissue of cows,which was significantly higher than other tissues(P<0.05).This study provides an important theoretical basis for the subsequent further study of the biological function and milk fat regulation mechanism of FABP4 in Holstein cows.

Key words: Holstein cows, FABP4, Cloning, Bioinformatics, Tissue expression profiling