Identification of genes induced by neuregulin in cultured myotubes

The formation of the neuromuscular junction (NMJ) involves a series of indu ctive interactions between motor neurons and muscle fibers. The neural sign als proposed to induce the mRNA expression of acetylcholine receptors in mu scle include neuregulin (NRG). In the present study, we have employed RNA f ingerprinting by arbitrarily primed PCR analysis to identify the differenti ally expressed transcripts following NRG treatment in cultured myotubes. Ni ne partial cDNA fragments were isolated; the mRNA expression of eight of th ese genes was found to be up-regulated by NRG. The spatial and temporal exp ression profiles of these NRG-regulated genes in rat tissues during develop ment suggest potential functional roles during the formation of NMJ in vivo . Our findings not only allowed the identification of novel genes, but also suggested possible functions for some known genes that are consistent with their potential roles at the NMJ. Furthermore, the identification of G-pro tein pi subunit and G-protein-coupled receptor as NRG-regulated genes has p rovided the first demonstration that activation of the NRG signaling pathwa y can induce the expression of components in the G-protein signaling cascad e.