MicroRNAs, alternative splicing and the muscle proteome

As reported in the January 1 issue of G&D, a UCLA research team led by Dr. Douglas Black has shown how microRNAs regulate alternative splicing during muscle development. The researchers determined that the muscle-specific microRNA miR-133 targets the alternative splicing factor, nPTB, during early myogenesis. The resulting decrease in nPTB protein levels alters the splicing of muscle-specific mRNAs in such a way as to promote muscle cell differentiation. The targeting of this splicing factor allows the microRNA to control a larger temporal program of muscle cell gene expression through not just the direct translational regulation of mRNAs, but also by altering the splicing of important mRNAs.