Human Fast Skeletal Myosin Light Chain 2 cDNA: Isolation, Tissue Specific Expression of the Single Copy Gene, Comparative Sequence Analysis of Isoforms and Evolutionary Relationships

Abstract

A cDNA clone encoding human fast skeletal myosin regulatory light chain (HSRLC) has been isolated and characterized from a fetal muscle cDNA library. The cDNA contains the coding sequence of 170 amino acids (aa) and 58 and 91 nucleotides in the 5' and 3' untranslated regions (UTRs), respectively. HSRLC is encoded by a single copy gene in the human genome and shows a tissue-specific pattern of expression in skeletal muscle. Comparison of derived amino acid sequence of HSRLC with database sequences reveals highly conserved 12 amino acid residues in a putative calcium-binding region. HSRLC is unique among all RLC sequences in having three consecutive potential phosphorylatable serine residues. The Cys-129 of HSRLC corresponds to the critical Gly-117 of scallop RLC that is essential for its regulatory function. The clusters of hydrophobic residues that are believed to stabilize the binding of NH2-terminal of RLC with myosin heavy chain show high sequence conservation in RLCs. Besides identifying specific targets for functional studies of HSRLC by mutagenesis, the results support the concept of an ancestral gene from which the RLC genes have evolved.

Genomic Organization, Intronic Duplications, and Promoter Characteristics of the Fast Skeletal Myosin Light Chain-2 Gene (mlc2f) from Javanese Ricefish Oryzias javanicus

“…However, the functional involvement of these TFs in the regulation of fish mlc2f genes has yet not been determined. In contrast, previous studies on the mammalian mlc2f have reported that downregulation of AP-1, Sp-1, and NF-κB should be a prerequisite for the onset of myocyte differentiation (Lehtinen et al, 1996;Sachdev et al, 2003).…”

Hydroxyl radical and glutathione interactions alter calcium sensitivity and maximum force of the contractile apparatus in rat skeletal muscle fibres

“…It is proposed that phosphorylation of the RLC increases Ca 2+ sensitivity by bringing the myosin heads into closer proximity with actin (MacIntosh, 2003), and it seems entirely plausible that glutathionylation of the RLC could have similar effects. Consistent with this, the RLC of fast‐twitch muscle has two cysteine residues to act as sites for glutathionylation, one of which (Cys‐129) is crucial to regulatory function (Sachdev et al 2003), whereas the RLC of slow‐twitch muscle has no cysteine residues at all (Dalla Libera et al 1989) and so could not be subject to glutathionylation.…”

Gene expression throughout a vertebrate's embryogenesis

“…Eight-hundred and eighty-nine genes (13.0%, p < 0.01) are significantly differently expressed during pre-hatching (stages 1-35) versus post-hatching (stages 36-40) (Figure 3); 417 genes (47%) have higher expression levels before hatching, while 472 genes (53%) are up regulated after hatching (Additional File 7). Several post-hatch up regulated genes have important functions in muscle tissue development and movement including parvalbumins alpha and beta (calcium-binding proteins involved in muscle relaxation have 5-9-fold higher expression post-hatch [10,11]), myosin regulatory light chain, skeletal muscle isoform (6.1-fold increase [12]), myosin light chain 3, skeletal muscle gene (5.2-fold increase [13]), myosin binding protein C (3.4-fold increase [14,15]) and troponins I, T and C (~3-fold increases [16]). Increased transcript levels of these genes suggest increases in movement and muscle activity of a free-swimming Fundulus compared to restricted movement within a chorion microenvironment before hatching.…”