Abstract
The histone H1 complement of Caenorhabditis elegans contains a single unusual protein, H1.X. Although H1.X possesses the globular domain and the canonical three-domain structure of linker histones, the amino acid composition of H1.X is distinctly different from conventional linker histones in both terminal domains. We have characterized H1.X in C. elegans by antibody labeling, green fluorescent protein fusion protein expression and RNA interference. Unlike normal linker histones, H1.X is a cytoplasmic as well as a nuclear protein and is not associated with chromosomes. H1.X is most prominently expressed in the marginal cells of the pharynx and is associated with a peculiar cytoplasmic cytoskeletal structure therein, the tonofilaments. Additionally H1.X::GFP is expressed in the cytoplasm of body and vulva muscle cells, neurons, excretory cells and in the nucleoli of embryonic blastomeres and adult gut cells. RNA interference with H1.X results in uncoordinated and egg laying defective animals, as well as in a longitudinally enlarged pharynx. These phenotypes indicate a cytoplasmic role of H1.X in muscle growth and muscle function.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antibody Specificity / genetics
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Antibody Specificity / immunology
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Caenorhabditis elegans / cytology
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Caenorhabditis elegans / metabolism*
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Caenorhabditis elegans Proteins / genetics
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Caenorhabditis elegans Proteins / isolation & purification*
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Cell Compartmentation / genetics
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Cell Nucleolus / metabolism
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Cell Nucleolus / ultrastructure
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Cytoskeleton / metabolism*
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Cytoskeleton / ultrastructure
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Genes / genetics
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Green Fluorescent Proteins
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HeLa Cells
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Histones / genetics
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Histones / isolation & purification*
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Humans
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Intermediate Filaments / metabolism
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Intermediate Filaments / ultrastructure
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Luminescent Proteins
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Molecular Structure
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Muscle Contraction / genetics
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Muscles / abnormalities
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Muscles / metabolism
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Muscles / ultrastructure
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Neurons / metabolism
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Neurons / ultrastructure
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Phenotype
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Protein Structure, Tertiary / genetics
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RNA Interference / physiology
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Urinary Tract / metabolism
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Urinary Tract / ultrastructure
Substances
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Caenorhabditis elegans Proteins
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Histones
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Luminescent Proteins
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Recombinant Fusion Proteins
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hil-1 protein, C elegans
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Green Fluorescent Proteins