title: Identification and expression profile of a novel alternative splicing of Pax7 in chick skeletal muscle.
abstract: Pax7 is essential for skeletal muscle myogenesis. The alternative splicing forms of Pax7 were found in human and mouse. In this study, we identified a new alternative splicing of chick Pax7. We named it Pax7-2 and localized it in the nucleus of chick myoblast. In Pax7-2 mRNA, exon 8 of chick Pax7 gene was spliced out. That led to a 22-amino acid deletion in the COOH terminal of Pax7-2 protein compared with Pax7 protein. Luciferase assays demonstrated that chick Pax7 could act as a transactivator and the deleted 22 amino acids in Pax7-2 may belong to the transactivation domain of Pax7. Pax7-2 lost transactivation ability. We detected the expression levels of Pax7-2 in chick pectoralis muscles at different developmental stages and found that the expression of Pax7-2 was at its peak in d-12 chick embryos. The expression levels of Pax7 and Pax-2 in chick pectoralis muscles at different developmental stages had a similar trend across the period under study, although the changes of their expression levels were different. As chicks grew up, Pax7 and Pax7-2 were expressed at much lower levels.
authors.affiliation: College of Biological Sciences and State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing, P. R. China.
authors.forename: C
authors.initials: C
authors.lastname: Mao
authors.forename: X
authors.initials: X
authors.lastname: Hu
authors.forename: N
authors.initials: N
authors.lastname: Li