Temporal expression of growth factor genes during myogenesis of satellite cells derived from the biceps femoris and pectoralis major muscles of the chicken

The expression of mRNAs for transforming growth factors (TGF-beta2, myostat in, activin-B, and follistatin), insulin-like growth factors (ICF-I and -II ), and fibroblast growth factor (basic, bFGF) was investigated in satellite cells derived from chicken pectoralis major (PM) and biceps femoris (BF) m uscles in the stages from initiation of proliferation to fusion. These grow th factor gene cDNAs were synthesized by reverse transcriptase polymerase c hain reaction (RT-PCR). No myostatin, activin-B, follistatin or bFGF expres sion was detected in either cell culture at 0 h. TGF-beta2 mRNA level incre ased at 48 h (P < 0.01) and remained constant through 144 h in both PM and BF satellite cell cultures. The ontogeny of myostatin gene expression with the exception of a sharp increase in BF culture at 72 h (P < 0.01), was nea rly identical in both cell cultures. Activin-B mRNA level in PM satellite c ells was higher than that in BF satellite cells at 72 h and 120 h (P < 0.01 ). Follistatin mRNA in PM satellite cells was higher than that in BF satell ite cells at 24, 96, and 120 h culture (P < 0.01). No IGF-I gene expression was detected in cell cultures at any time point. IGF-II gene expression in BF satellite cells declined at 96 h (P < 0.01) and remained reduced until 144 h. bFGF mRNA in both satellite cell cultures increased at 24 h (P < 0.0 5) and remained at this level in BF satellite cells through 144 h. J. Cell. Physiol. 186:146-152, 2001. (C) lear Wiley-Liss, Inc.