Figure 6

Sustained HMGA1a-eGFP expression interferes with the expression of myogenic genes. (A) Comparison of expression profiles of myogenic transcription factors in myoblasts (day 0) and during differentiation (days 1, 3, 6, 9 after induction). Gene expression was analyzed by RT-PCR as described in Fig. 1. Genes analyzed were: myogenic factors 5 and 6 (Myf5 and Myf6), the myocyte enhancer factor 2A (Mef2a), myogenic determination gene 1 (MyoD), myogenin and homeobox, msh-like 1 (Msx1). Note the specific down-regulation of MyoD and myogenin and the up-regulation of the myogenic inhibitor Msx1 in C2A1a cells. As loading control Gapdh expression is shown. (B) Expression profiles of components of the Igf-system in C2C12 and C2A1a cells at the time points described in (A). Genes analyzed were: insulin-like growth factors 1 and 2 (Igf1 and Igf2) and Igf binding proteins 1, 2 and 3 (Igfbp1, Igfbp2 and Igfbp3). Note the suppression of Igf1, Igf2, Igfbp2 and Igfbp3. Gapdh expression is presented as a control.