Organization of human and mouse skeletal myosin heavy chain gene clusters is highly conserved

Abstract

Myosin heavy chains (MyHCs) are highly conserved ubiquitous actin-based motor proteins that drive a wide range of motile processes in eukaryotic cells. MyHC isoforms expressed in skeletal muscles are encoded by a multigene family that is clustered on syntenic regions of human and mouse chromosomes 17 and 11, respectively. In an effort to gain a better understanding of the genomic organization of the skeletal MyHC genes and its effects on the regulation, function, and molecular genetics of this multigene family, we have constructed high-resolution physical maps of both human and mouse loci using PCR-based marker content mapping of P1-artificial chromosome clones. Genes encoding six MyHC isoforms have been mapped with respect to their linear order and transcriptional orientations within a 350-kb region in both human and mouse. These maps reveal that the order, transcriptional orientation, and relative intergenic distances of these genes are remarkably conserved between these species. Unlike many clustered gene families, this order does not ref lect the known temporal expression patterns of these genes. However, the conservation of gene organization since the estimated divergence of these species (Ϸ75-110 million years ago) suggests that the physical organization of these genes may be significant for their regulation and function.

Muscle fibre ontogenesis in farm animal species

“…This is likely the result of gene conversion-like events within each gene family. It is consistent with the observation that the fast and slow MHC genes are arranged in two clusters on different chromosomes [49,80,96,97]. In mammals, the cardiac alpha-MHC gene is closely linked to the beta/slow -MHC gene, on chromosome 14 in both humans and mice, and on chromosome 7 in 419 ® ® ® ® ® ® correlation generally exists between fibre diameter and the oxidative metabolism to facilitate the diffusion of oxygen to the mitochondria.…”

Differential expression of lipid metabolism-related genes and myosin heavy chain isoform genes in pig muscle tissue leading to different meat quality

“…MyHC isoform genes and PGC-1α expression in LM Eight isoforms of MyHC encoded by a separate gene are found in the skeletal muscles of mammals (Weiss et al, 1999;Shrager et al, 2000). In postnatal pigs, skeletal muscle consists of four MyHC isoforms: MyHCI, MyHCIIa, MyHCIIx and MyHCIIb, with different biochemical and biophysical characteristics such as oxidative and glycolytic capacities, contraction speed, cross-sectional area and TG content (Schiaffino and Reggiani, 1996;Lefaucheur et al, 2002;Lefaucheur, 2010).…”

TnIfast IRE enhancer: Multistep developmental regulation during skeletal muscle fiber type differentiation

“…Third, a differential augmentation of expression occurs during the early postnatal maturation of the fast fiber population, giving rise to a IIBϾIIXϾIIA differential expression pattern. It is interesting to note that each of these three developmental steps is spatiotemporally associated with one of three developmental regulatory events at the fast MHC gene cluster (Weydert et al, 1987;Russell et al, 1988;Condon et al, 1990a;LaFramboise et al, 1991;Weiss et al, 1999). These are, in corresponding order: First, tissue-specific activation of the fast MHC gene cluster during myoblast differentiation, with resultant expression of the MHCemb gene; Second, activation of the MHCperi gene during formation of secondary fibers; Third, differential activation of the adult fast MHC isoforms IIB, IIX, and IIA during early postnatal maturation of the fast fiber population.…”