Disease relevance of let-75

• The complete coding sequence of Onchocerca volvulus myosin heavy chain has been determined from a series of overlapping cDNAs [1].

High impact information on let-75

• Sequence analysis of 16 sdc-3 alleles reveals that the dosage compensation mutations specifically eliminate a pair of zinc finger motifs at the carboxyl terminus of Sdc-3, while the sex determination mutations after a region with limited homology to the ATP-binding domain of myosin [2].
• Since this end of the gene corresponds to the 5' end of the coding sequence, these suppressor mutations probably result in amino acid substitutions in the globular head of the myosin molecule, and should be of value in studies of myosin force generation [3].
• Periodic charge distributions in the myosin rod amino acid sequence match cross-bridge spacings in muscle [4].
• The location of the protein in the A-band, along with earlier genetic data, suggests that the unc-22 product may interact with myosin to regulate its function [5].
• Here, we describe a new muscle LIM domain protein, UNC-95, and identify it as a novel target for the RING finger protein RNF-5 in the Caenorhabditis elegans body wall muscle. unc-95(su33) animals have disorganized muscle actin and myosin-containing filaments as a result of a failure to assemble normal muscle adhesion structures [6].

Biological context of let-75

• We have used transformation-rescue and lacZ fusion assays to determine sequence requirements for regulated myosin gene expression during development [7].
• To further characterize the myosin gene promoters and to examine the types of enhancer sequences in the genome, we have initiated a screen of C. elegans genomic DNA for fragments capable of enhancing the myo-2 promoter [7].
• Myosin heavy chain gene amplification as a suppressor mutation in Caenorhabditis elegans [8].
• The encoded amino acid substitutions of s95 and s74 are in the 23 X 10(3) Mr and 50 X 10(3) Mr domains of the myosin head, flanking the ATP binding site [9].
• The three deletion mutations were found in a region of the myosin rod with numerous direct and inverted nucleotide sequence repeats, but their origin cannot be accounted for by homologous recombination [9].

Anatomical context of let-75

• MHC C and MHC D are exclusively produced in the pharyngeal muscle [10].
• The unc-54 gene of Caenorhabditis elegans encodes an abundant myosin heavy chain protein expressed in body-wall muscle cells [11].
• By 38 hr, decreased synthesis of myosin B is detected in the unc-52 mutant SU200, when sarcomere growth slows considerably [12].
• Hydrophobicity variations along the surface of the coiled-coil rod may mediate striated muscle myosin assembly in Caenorhabditis elegans [13].
• Reducing the function of mlc-4 or nmy-2, a nonmuscle myosin II gene, also leads to a loss of polarized cytoplasmic flow in the C. elegans zygote, supporting models in which cytoplasmic flow may be required to establish a-p differences [14].

Associations of let-75 with chemical compounds

• The mutation e1662 is an allele of the Caenorhabditis elegans unc-54 gene induced with the difunctional alkylating agent 1,2,7,8-diepoxyoctane. unc-54 encodes the major myosin heavy chain isozyme of body wall muscle cells [15].
• Intron positions are conserved in the 5' end region of myosin heavy-chain genes [16].
• Light meromyosin (LMM), prepared by limited tryptic digestion of myosin, usually contains several polypeptide chains, LMM-A, LMM-B, and LMM-C in decreasing order of molecular weight estimated from sodium dodecyl sulfate-gel electrophoresis [17].
• Myosin heavy chain kinase A (MHCK A) in Dictyostelium was identified as a biochemical activity that phosphorylates threonine residues in the myosin II tail domain and regulates myosin filament assembly [18].
• Myosin rod was carboxymethylated with radioactive iodoacetic acid under various conditions [19].

Regulatory relationships of let-75

• Within the 5' flanking sequence homology to actin and the homology 2 block of the major myosin gene (unc-54) is noted [20].

Other interactions of let-75

• Comparison of the unc-54 protein sequence with the sequence of a second myosin heavy chain from nematode, indicates that the globular head sequence S-1 is more highly conserved than the alpha-helical coiled-coil rod [21].
• We show that C. elegans IP(3)Rs, encoded by the gene itr-1, interact directly with myosin II [22].
• The thick filaments of the nematode, Caenorhabditis elegans, arising predominantly from the body-wall muscles, contain two myosin isoforms and paramyosin as their major proteins [23].
• Caenorhabditis elegans body wall muscle contains two isoforms of myosin heavy chain, MHC A and MHC B, that differ in their ability to initiate thick filament assembly [13].
• Using RNA-mediated genetic interference in a phenotypic screen, we identified a conserved nonmuscle myosin II regulatory light chain gene in Caenorhabditis elegans, which we name mlc-4 [14].

Analytical, diagnostic and therapeutic context of let-75

• Sequence analysis of the complete Caenorhabditis elegans myosin heavy chain gene family [24].
• We describe the dissection of a body muscle-specific enhancer sequence contained within the Caenorhabditis elegans myosin heavy chain gene unc-54 [25].
• Based on homology data, structural location, competitive ELISA, and immunoblot we conclude that WbN1 is related to myosin or a similar myofibrillar protein [26].
• We show that structural protein arrays consisting largely of collagen, myosin, and tubulin, and their associated proteins can be imaged in three dimensions with high contrast and resolution by laser-scanning second harmonic generation (SHG) microscopy [27].
• The molecular cloning and determination of the complete sequences of the genes encoding the four isoforms of myosin heavy chain and of the myosin-associated protein paramyosin have been a major landmark [28].

References