Abstract
In Schizosaccharomyces pombe, rad18 is an essential gene involved in the repair of DNA damage produced by ionizing radiation and in tolerance of UV-induced DNA damage. The Rad18 protein is a member of the SMC (structural maintenance of chromosomes) superfamily, and we show that, like the other SMC proteins in condensin and cohesin, Rad18 is a component of a high-molecular-weight complex. This complex contains at least six other proteins, the largest of which is Spr18, a novel SMC family member closely related to Rad18, and likely to be its heterodimeric partner. SMC proteins have ATP-binding domains at the N- and C-termini, and two extended coiled-coil domains separated by a hinge in the middle. We show that the N-terminal ATP-binding domain of Rad18 is essential for all functions, and overexpression of an N-terminal mutant has a dominant-negative effect. We have identified an important mutation (S1045A) near the C-terminus of Rad18 that separates its repair and essential roles. Potential models for the role of the Rad18-Spr18 complex during DNA repair are discussed.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Triphosphatases / chemistry
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Adenosine Triphosphatases / genetics
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Adenosine Triphosphatases / metabolism
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Amino Acid Sequence
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Cell Cycle Proteins*
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Chromosomal Proteins, Non-Histone / chemistry*
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Chromosomal Proteins, Non-Histone / genetics
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Chromosomal Proteins, Non-Histone / metabolism*
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DNA Repair
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DNA-Binding Proteins / chemistry*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Fungal Proteins / chemistry*
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Fungal Proteins / genetics
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Fungal Proteins / metabolism*
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Genes, Fungal
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Genetic Complementation Test
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Macromolecular Substances
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Molecular Sequence Data
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Molecular Weight
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Mutagenesis, Site-Directed
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Phenotype
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Saccharomyces cerevisiae Proteins*
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Schizosaccharomyces / genetics
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Schizosaccharomyces / metabolism*
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Schizosaccharomyces pombe Proteins*
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Sequence Homology, Amino Acid
Substances
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Cell Cycle Proteins
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Chromosomal Proteins, Non-Histone
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DNA-Binding Proteins
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Fungal Proteins
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Macromolecular Substances
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RAD18 protein, S cerevisiae
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Saccharomyces cerevisiae Proteins
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Schizosaccharomyces pombe Proteins
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Smc5 protein, S pombe
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Adenosine Triphosphatases