Estudio de la función de Myf5 en el desarrollo de la musculatura de las extremidades

Abstract

Skeletal myogenesis in vertebrates is coordinated by the activation of a cascade of the four Myogenic Regulatory Factors (MRFs): Myf5, Mrf4, MyoD and MyoG. These transcription factors bind DNA and activate the expression of specific genes in particular progenitor cells that will give rise to the different muscles in the adult body. The MRFs’ cascade is initiated by Myf5, the first factor to be expressed in the embryo. We and others have extensively studied the complex transcriptional regulation of the Myf5/Mrf4 locus using transgenic mice. Nowadays, we know that there are more than 25 regulatory elements controlling the expression of Mrf4 and Myf5 in a specific time frame and in particular embryonic progenitors. One of these regulatory elements is a limb enhancer located 57 kb upstream of the Myf5 transcriptional start site. This enhancer controls Myf5 expression in limbs during development. While the mechanisms involved in the spatiotemporal regulation of Myf5 have been extensively studied at both single-enhancer and global regulatory levels, the function of Myf5 in different subpopulations of muscle progenitor cells is still not explored. This project focuses on the generation and initial characterization of new alleles to study Myf5 function: a line in which the limb enhancer has been removed from the genome by CRISPR/Cas9, a line in which a FLAG tag has been fused with the Myf5 gene and some novel mutant lines with a functional deletion of Myf5, in which no surrounding enhancer has been removed.