Prokaryotic expression of FAT/CD36 fusion protein and the specific effects on the deposition of visceral fat in cockerel chicks.

【Objective】Fatty Acid Translocase (FAT/CD36) is an important carrier protein involved in the transmembrane transportation of fatty acids and cellular triglyceride accumulation. This experiment was designed to get a better understanding of the role of FAT/CD36 in the adipose deposition by active immunization method. 【Method】Chicken FAT/CD36 extracellular antigen domain partial gene fragment was cloned, inserted into the prokaryotic expression vector pET-32a(+) between BamHⅠand XhoⅠsites, and translated in Escherichia coli BL21 (DE3). Then, sixty 22-day-old yellow-feathered broilers were randomly divided into male, female control groups and two experiment groups inoculated i.m. with 1 mg of the chicken FAT/CD36 and bovine serum albumin (BSA) immunogens on 34 d, 49 d and 63 d, respectively. At the end of trial, all birds were sacrificed for the fat deposition evaluation. 【Result】 A 29 kD recombinant chicken FAT/CD36 fusion protein was expressed in Escherichia coli BL21 (DE3). After induced for 6 hours by adding IPTG to a final concentration of 0.1 mmol·L-1, the fusion protein amounted up to 32% of the total bacterial protein expressed and existed mainly in inclusion body, which was further purified by affinity chromatography and dialysis. The levels of serum anti-FAT/CD36 antibody in both male and female treatment groups gradually elevated and were significantly higher than that in each control group after the first immunization. It was interesting to find that the active immunization of FAT/CD36 specifically decreased the percentage of visceral fat in male but not female broilers, whereas the thickness of subcutaneous fat was unchanged. 【Conclusion】 The results indicated the role of chicken FAT/CD36 in the regulation of adiposewith gender- and site-specific manner, which provided a further understanding of the fat deposition mechanism in avian.