Promoter analysis of bovine cardiomyopathy-associated protein 1 gene.

The CMYA1 (cardiomyopathy-associated protein 1) is an actin-binding protein that plays a vital role in cardiac morphogenesis. CMYA1 is expressed specifically in the myocardial and skeletal muscle and is up-regulated in injured muscle. We therefore speculated that the bovine CMYA1 promoter might be muscle-specific. In this study, the promoter (+20/-1135) region of the bovine CMYA1 gene was cloned into a pEGFP-1 vector, and we found that the EGFP was observed only in C2C12 and myoblast cells. Thus, the CMYA1 promoter is muscle-specific. Thereafter, eight pGL3-basic vectors with various truncated CMYA1 promoter fragments were transfected into C2C12 cells, to identify the core promoter region using a Dual-Luciferase Reporter Assay System. The results showed that the promoter region from -457 to +20 bp was essential for CMYA1 to maintain the promoter activity, implying that this region may be the CMYA1 core promoter. We thus illustrate that the core promoter is muscle-specific. To evaluate the activity of the CMYA1 core promoter, the CMYA1 core and muscle creatine kinase (MCK) promoters were cloned into a pcDNA3.1 vector. The expression levels of their target genes were measured in C2C12 cells using real-time polymerase chain reaction. The CMYA1 promoter drove the expression of the target gene six times higher than did the MCK promoter. The results thus suggest that the CMYA1 promoter could be an effective muscle-specific promoter, which may be useful in further studies of cardiomyopathy treatment and transgenic animal research.

Overexpression of the A-FABP gene facilitates intermuscular fat deposition in transgenic mice.

Adipocyte fatty acid-binding protein (A-FABP), the most abundant FABP in adipocytes, controls fatty acid uptake, transport, and metabolism in fat cells. We constructed a transgenic mice model that overexpressed the cattle A-FABP gene to investigate the relationship between A-FABP expression and intermuscular fat deposition. There was no significant difference in body weight and serum biochemical indexes between transgenic and wild-type mice. Further, there were no significant differences in intermuscular triglyceride content and A-FABP expression levels over three generations of transgenic mice. However, abdominal adipose rate, A-FABP protein content, and intermuscular triglyceride levels of transgenic mice were significantly higher than those of wild-type mice. In addition, triglycerides were remarkably higher in the skeletal muscle but lower in the myocardium of transgenic mice. Thus, overexpression of cattle A-FABP gene promoted fat deposition in the skeletal muscle of transgenic mice.