PROMOTER SELECTION AND ALTERNATIVE PRE-mRNA SPLICING ARE USED TO GENERATE COMPLEX CONTRACTILE PROTEIN PHENOTYPES

Abstract

Publisher Summary This chapter describes the use of promoter selection and alternative pre-mRNA splicing to generate complex contractile protein phenotypes. The regulated expression of structurally distinct developmentally regulated and cell type-specific protein isoforms is a fundamental characteristic of eukaryotic cells. The molecular mechanisms responsible for generating this protein diversity might be broadly categorized into two main systems: those that select a particular gene among the members of a multigene family for expression in a particular cell and those that generate several different proteins from a single gene. The latter mechanism includes DNA rearrangement and alternative pre-mRNA splicing, each producing the differential use of intragenic sequences that lead to the production of multiple protein isoforms from a single gene. DNA rearrangement appears to be restricted to a very limited set of genes coding for immunoglobulins and T-cell receptors. In contrast, the increasing numbers of genes in organisms ranging from Drosophila to human, including their RNA and DNA viruses, are known to be alternatively spliced. The restricted combinatorial use of the different members of these multigene families allows for the generation of a moderate number of qualitatively different sarcomere types that, at least in some cases, exhibit significantly different physiological characteristics.