Expression of PDLIM5 Spliceosomes and Regulatory Functions on Myogenesis in Pigs

Meat yield, determined by muscle growth and development, is an important economic trait for the swine industry and a focus of research in animal genetics and breeding. PDZ and LIM domain 5 (PDLIM5) are cytoskeleton-related proteins that play key roles in various tissues and cells. These proteins have multiple isoforms, primarily categorized as short (PDLIM5-short) and long (PDLIM5-long) types, distinguished by the absence and presence of an LIM domain, respectively. However, the expression patterns of swine PDLIM5 isoforms and their regulation during porcine skeletal muscle development remain largely unexplored. We observed that PDLIM5-long was expressed at very low levels in pig muscles and that PDLIM5-short and total PDLIM5 were highly expressed in the muscles of slow-growing pigs, suggesting that PDLIM5-short, the dominant transcript in pigs, is associated with a slow rate of muscle growth. PDLIM5-short suppressed myoblast proliferation and myogenic differentiation in vitro. We also identified two single nucleotide polymorphisms (-258 A > T and -191 T > G) in the 5' flanking region of PDLIM5, which influenced the activity of the promoter and were associated with muscle growth rate in pigs. In summary, we demonstrated that PDLIM5-short negatively regulates myoblast proliferation and differentiation, providing a theoretical basis for improving pig breeding programs.