The Control of muscle gene expression: A review of molecular studies on the processing of primary transcripts

Many muscle proteins exist as multiple isoforms. This diversity is generated by the presence of multigene families and by alternative splicing of individual genes. Examples are given of different modes of alternative splicing undergone by the primary transcripts of muscle genes, and preliminary studies on the mechanism are mentioned. The chromosomal organization of muscle genes is discussed briefly. Studies on their transcriptional regulation are reviewed first in terms of cis-acting sequences in the proximal promoter region and elsewhere in the vicinity of the gene, which are necessary for its expression, and, secondly, in terms of trans-acting transcriptional factors which interact with such sequences. Molecular regulation of splicing and of transcription is discussed mainly with reference to the muscle genes of mammals.