Multiple alternative splicing and differential expression of actinin-associated LIM protein (ALP) during porcine skeletal muscle development in vitro and in vivo

The actinin-associated LIM protein (ALP) is co-localized with α-actinin at the Z-discs and plays a critical role in the integration of cytoskeletal architecture and transcriptional regulation. Here we report that five isoforms of the porcine ALP were generated in skeletal muscle by alternative splicing. All of ALP isoforms were predominantly expressed in skeletal muscle except for ALP2. These isoforms had different expression profiles during the prenatal and postnatal period of the porcine skeletal muscle development and between the two breeds. Moreover, ALP1 and ALP3 were expressed at higher levels in soleus and masseter muscles compared with longissimus dorsi and bicepsfemoris muscles in Yorkshire pigs. Expression analysis in porcine satellite cells showed that all isoforms were induced in differentiated porcine satellite cells, suggesting a role of them in myogenic differentiation. These results provide new insight into roles of regulation at level of splicing of the ALP in governing porcine skeletal muscle development.