Cloning of the heart fatty acid-binding protein (H-FABP) gene and its tissue-specific expression profile in the Lanzhou fat-tailed sheep, Ovis aries

Abstract

The heart fatty acid-binding protein gene (h-fabp) plays an important role in intracellular fatty acid transport. h-fabp had been cloned and sequenced and is considered a functional candidate gene for assessing the meat quality traits in pig, chicken, and cattle. However, there have only been few studies reported on this gene in sheep. In the present study, we cloned the full-length cDNA of h-fabp in the Lanzhou fat-tailed sheep using RACE technique. Its tissue specific expression profile in the skeletal muscle, liver and 4 fat depots at seven developmental stages was determined by real-time quantitative PCR. A 425bp 5′-RACE cDNA, 231bp 3′-RACE cDNA and 177bp intermediate fragment were spliced to obtain a 748bp full-length cDNA of h-fabp (GenBank accession number JQ780322). The phylogenetic analysis revealed that the Lanzhou fat-tailed sheep is more closely related to the goat, Capra hircus. In skeletal muscle, h-fabp was expressed at a very low level in one-month-old sheep. The expression level increased in three- and five-month-old sheep, and a peak expression level was observed in seven-month-old sheep. In nine- and eleven-month-old sheep, the gene expression level was similar to the mRNA level observed in three- and five-month-old sheep. In thirteen-month-old sheep, the h-fabp mRNA level was similar to the low expression level observed in one-month-old sheep. The expression pattern observed in the skeletal muscle at different developmental stages in sheep indicates that h-fabp expression declines with age. A similar conclusion on the h-fabp expression pattern in the liver was drawn from our findings in this study. The amount of h-fabp mRNA in the subcutaneous (s.c.) and visceral (v.s.) depots at each developmental stage was very low, and there was no significant difference in the expression levels among these depots. When we added the data from the seven developmental stages together, however, the highest h-fabp expression level was observed in the s.c. fat near the wither (s.c.W), followed by the v.c. perirenal (v.c.P), v.c. omental (v.c.O), and s.c. fat near the base of tail (s.c.T). These findings provide basic data that may be useful in future studies that investigate the role h-fabp plays in fat deposition and the regulation of fatty acid metabolism in sheep.