Grant: CIHR Fellowship

Satellite cells (SCs) are stem cells required for growth, maintenance, and regeneration of skeletal muscle. In response to molecular triggers from injuries or disease, subsets of SCs activate and have the ability to self renew, proliferate as myoblasts, or undergo myogenic differentiation to regenerate damaged tissue. Central to the specification and function of SCs is the PAX3 transcription factor, which activates factors that mediate migration of muscle progenitor cells during development. In adult SCs however, PAX3 expression is down-regulated in all but a few muscle groups, such as the diaphragm muscle. Pax3 expression is controlled via alternative polyadenylation of its 3'untranslated region (3'UTR). We hypothesize that the poly-A binding protein, PABPN1, mediates Pax3 3'UTR alternative polyadenylation. Transient expression of PAX3 is associated with SC activation and corresponds with a proliferative state of myoblasts. Thus, PABPN1 may also regulate SC function.