Abstract
Mutations in the unc-52 gene of Caenorhabditis elegans affect attachment of the myofilament lattice to the muscle cell membrane. Here, we demonstrate that the unc-52 gene encodes a nematode homolog of perlecan, the mammalian basement membrane heparan sulfate proteoglycan. The longest potential open reading frame of this gene encodes a 2482-amino-acid protein with a signal peptide and four domains. The first domain is unique to the unc-52 polypeptide, whereas the three remaining domains contain sequences found in the LDL receptor (domain II) laminin (domain III) and N-CAM (domain IV). We have identified three alternatively spliced transcripts that encode different carboxy-terminal sequences. The two larger transcripts encode proteins containing all or part of domain IV, whereas the smaller transcript encodes a shortened polypeptide that completely lacks domain IV. We have determined that the disorganized muscle phenotype observed in unc-52(st196) animals is caused by the insertion of a Tc1 transposon into domain IV. Two monoclonal antibodies that recognize an extracellular component of all contractile tissues in C. elegans fail to stain embryos homozygous for a lethal unc-52 allele. We have mapped the epitopes recognized by both monoclonal antibodies to a region of domain IV in the unc-52-encoded protein sequence.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Actin Cytoskeleton / chemistry
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Amino Acid Sequence
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Animals
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Basement Membrane / chemistry*
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Caenorhabditis elegans / genetics*
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Caenorhabditis elegans Proteins*
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Cell Adhesion Molecules, Neuronal / chemistry
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Cloning, Molecular
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Conserved Sequence
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DNA Transposable Elements
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Genes, Helminth*
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Helminth Proteins / chemistry*
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Helminth Proteins / genetics
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Heparan Sulfate Proteoglycans*
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Heparitin Sulfate / chemistry*
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Heparitin Sulfate / genetics
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Immunoglobulins / chemistry
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Immunoglobulins / genetics
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Laminin / chemistry
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Membrane Proteins / chemistry
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Membrane Proteins / genetics
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Molecular Sequence Data
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Muscle Contraction / genetics
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Muscle Proteins / chemistry*
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Mutagenesis, Insertional
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Open Reading Frames
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Proteoglycans / chemistry*
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Proteoglycans / genetics
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Receptors, LDL / chemistry
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Recombinant Fusion Proteins / chemistry
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Sequence Analysis, DNA
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Sequence Homology, Amino Acid
Substances
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Caenorhabditis elegans Proteins
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Cell Adhesion Molecules, Neuronal
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DNA Transposable Elements
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Helminth Proteins
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Heparan Sulfate Proteoglycans
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Immunoglobulins
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Laminin
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Membrane Proteins
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Muscle Proteins
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Proteoglycans
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Receptors, LDL
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Recombinant Fusion Proteins
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unc-52 protein, C elegans
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perlecan
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Heparitin Sulfate
Associated data
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GENBANK/L11593
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GENBANK/L11594
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GENBANK/L13458
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GENBANK/L15616
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GENBANK/L16016
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GENBANK/L24529
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GENBANK/S56762
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GENBANK/S56763
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GENBANK/Z15047
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GENBANK/Z15048