Cloning of novel injury-regulated genes - Implications for an important role of the muscle-specific protein skNAC in muscle repair

To gain insight into the molecular mechanisms underlying the wound repair p rocess, we searched for genes that are regulated by skin injury. Using the differential display reverse transcription-polymerase chain reaction techni que, we identified a gene that was strongly induced as early as 12 h after wounding. Sequence analysis revealed the identity of the corresponding prot ein with skeletal muscle nascent polypeptide-associated complex (skNAC), a recently identified muscle-specific transcription factor. By in situ hybrid ization and immunohistochemistry, we demonstrated the specific expression o f skNAC in skeletal muscle cells of the panniculus carnosus at the wound ed ge. Furthermore, in vitro studies with cultured myoblasts revealed expressi on of skNAC in differentiating and differentiated, but not in proliferating , nondifferentiated cells. Differentiation of cultured myoblasts was accomp anied by simultaneous expression of skNAC and the muscle-specific transcrip tion factor myogenin. Our results provide the first evidence for a role of skNAC in muscle repair processes. Furthermore, they demonstrate the usefuln ess of our approach in identifying new players in wound repair.