Disease relevance of paramyosin

• Short probes recovered from the library were used to identify bacteriophage lambda and cosmid clones that encompass the entire paramyosin (unc-15) gene [1].
• To determine the extent of homology at the protein level, we screened a cDNA library of O. volvulus with an antiserum made against D. immitis paramyosin [2].

High impact information on paramyosin

• Mutant embryos in which cleavage arrests prematurely also generate cells that produce myosin and paramyosin [3].
• Specific antibodies to myosin and paramyosin, major protein constituents of differentiated muscle, react with mesodermal cells in wild-type embryos towards the end of the first half of embryogenesis [3].
• In CB1214 mutants where paramyosin is absent, beta-filagenin assembled with myosin to form abnormal tubular filaments with a periodicity identical to wild type [4].
• Within these regions, MHC A displays a more hydrophobic rod surface, making it more similar to paramyosin, which forms the thick filament core [5].
• The organization of myosin heavy chains (mhc) A and B and paramyosin (pm) which are the major proteins of thick filaments in adult wild-type Caenorhabditis elegans were studied during embryonic development [6].

Biological context of paramyosin

• All three regions contain three copies of a Ser-*-Ser-*-Ala motif, the most likely target for phosphorylation in paramyosin, suggesting that these regions may be modified by the same kinase [7].
• The Caenorhabditis elegans paramyosin gene (unc-15) was identified by screening with specific antibodies an "exon-expression" library containing lacZ/nematode gene fusions [1].
• Analysis of the in vitro phosphorylated paramyosin in comparison with the DNA sequence of the unc-15 paramyosin gene of C. elegans shows that serine residues in the non-alpha-helical N-terminal region are the targets of the kinase [7].
• Myosin isoforms A and B are located at the surface of the central and polar regions, respectively, of thick filaments in body muscle cells of Caenorhabditis elegans, whereas paramyosin and a distinct core structure comprise the backbones of these filaments [8].
• Prior studies have shown that such immunization stimulates a much stronger antibody response to recombinant and native filarial paramyosin than that seen after normal infection [9].

Anatomical context of paramyosin

• Myosin heavy chains A and B and paramyosin proteins appear to be compatible with functionally and structurally distinct muscle cell types that arise by multiple developmental pathways [10].
• By polarized light microscopy of body wall muscle, unc-96 mutants display reduced myofibrillar organization and characteristic birefringent "needles." By immunofluorescent staining of known myofibril components, unc-96 mutants show major defects in the organization of M-lines and in the localization of a major thick filament component, paramyosin [11].
• A region of the myosin rod important for interaction with paramyosin in Caenorhabditis elegans striated muscle [12].
• In the present study, we demonstrate the B cell epitope of paramyosin recognized by SJ18 epsilon [13].
• The thick (myosin) myofilaments show a variable length (from 2.2 microns up to 6 microns) and width (from 14 nm up to 231 nm) and contain a central core of paramyosin, which is absent in vertebrate muscles [14].

Associations of paramyosin with chemical compounds

• Here we describe the structure of the gene coding for the paramyosin of T. solium [15].
• Several leucine zippers are located on the hydrophobic face of the alpha-helix in paramyosin which, together with disulfide bonds between cysteines, are probably involved in the stabilization of the dimer [16].
• We have characterized 20 ethyl methanesulfonate-induced mutations in essential genes closely linked to unc-15 [17].

Physical interactions of paramyosin

• The major paramyosin species interacts with the two genetically specified myosin heavy chain isoforms [18].

Regulatory relationships of paramyosin

• In mutants that do not express MHC B or that express defective paramyosin, muscle structure is disrupted and movement is impaired [19].

Other interactions of paramyosin

• The N-terminal region of paramyosin has significant similarity to the non-helical C-terminal region of the two body wall myosin heavy chains of C. elegans [7].
• Similar calculations suggest optimal interactions between paramyosin molecules and myosin rods and in their anti-parallel alignments [1].
• The six proteins also cosedimented with thick filaments purified by gradient centrifugation from CB190 mutants lacking myosin heavy chain B and from CB1214 mutants lacking paramyosin [20].
• The suppression pattern of the suppressor against the two muscle-affecting genes, unc-15 and unc-52, suggested that either the suppressors are expressed in a developmental stage-specific manner or that the unc-52 products are expressed in cell-types other than muscle, possibly hypodermis [21].
• In the 0.65 map-unit interval around unc-15 defined by dpy-14 and unc-56, seven newly identified genes have been mapped relative to five existing genes [17].

Analytical, diagnostic and therapeutic context of paramyosin

• Paramyosin gene (unc-15) of Caenorhabditis elegans. Molecular cloning, nucleotide sequence and models for thick filament structure [1].
• Vaccination with recombinant filarial paramyosin induces partial immunity to Brugia malayi infection in jirds [9].
• Further epitope mapping carried out by a multi-pin system using heptameric peptides synthesized sequentially from 71 amino acids of paramyosin (Asp343-Ala413) demonstrated significant binding of SJ18 epsilon [13].
• Partial sequence determination of a 2.0 kb cDNA clone for an O. volvulus protein that induces an immunodominant response in rabbits revealed that this antigen has sequence similarities with Caenorhabditis elegans myosin and with schistosome paramyosin (which confers partial protection against schistosome infection) [22].
• In situ hybridization to Drosophila tissue sections shows that standard paramyosin is expressed in all larval and adult muscle tissues whereas miniparamyosin is restricted to a subset of the adult musculature [23].

References