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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Eleven suppressors of the radiation sensitivity of Saccharomyces cerevisiae diploids lacking the Srs2 helicase were analyzed and found to contain codominant mutations in the RAD51 gene known to be involved in recombinational repair and in genetic recombination. These mutant alleles confer an almost complete block in recombinational repair, as does deletion of RAD51, but heterozygous mutant alleles suppress the defects of srs2::LEU2 cells and are semidominant in Srs2+ cells. The results of this study are interpreted to mean that wild-type Rad51 protein binds to single-stranded DNA and that the semidominant mutations do not prevent this binding. The cloning and sequencing of RAD51 indicated that the gene encodes a predicted 400-amino-acid protein with a molecular mass of 43 kDa. Sequence comparisons revealed homologies to domains of Escherichia coli RecA protein predicted to be involved in DNA binding, ATP binding, and ATP hydrolysis. The expression of RAD51, measured with a RAD51-lacZ gene fusion, was found to be UV- and gamma-ray-inducible, with dose-dependent responses.
Mol Cell Biol 1992 Jul
PMID:Semidominant suppressors of Srs2 helicase mutations of Saccharomyces cerevisiae map in the RAD51 gene, whose sequence predicts a protein with similarities to procaryotic RecA proteins. 162 Jan 27

Cell cycle parameters in different radiation-sensitive strains of diploid yeast were determined by flow cytofluorometry. The cell generation time was increased in homozygous rad2 and rad51 mutants but was not significantly different from the wild type in rad9 and rad6 mutants. All mutants had a longer G1-phase than the wild type. A lengthened S-phase was found in rad2 cells. Rad51 mutants displayed a considerably longer duration of G2.
Mol Gen Genet 1984
PMID:Cell cycle parameters in radiation sensitive strains of Saccharomyces cerevisiae. 636 98

The genes of the Saccharomyces cerevisiae RAD52 epistasis group are required for the repair of ionizing radiation-induced DNA damage. Three of these genes, RAD51, RAD55, and RAD57, have been identified as putative RecA homologs. An important feature of RecA is its ability to bind and hydrolyze ATP. RAD55 and RAD57 contain putative nucleotide binding motifs, and the importance of these motifs was determined by constructing site-directed mutations of the conserved lysine residue within the Walker A-box. Changing the lysine residue to arginine or alanine resulted in a mutant phenotype in DNA repair and sporulation for Rad55 but not for Rad57. Protein-protein interactions among Rad51, Rad55, and Rad57 were tested for by the two-hybrid system. Rad55 was shown to interact with Rad51 and Rad57 but not with itself. Additionally, no interaction between Rad57 and Rad51 or between Rad57 and itself was detected. Consistent with the hypothesis that Rad55 and Rad57 may function within, or stabilize, a protein complex, we found that RAD51 expressed from a high-copy-number plasmid suppresses the DNA repair defect of strains carrying rad55 and rad57 mutations. These data, in conjunction with other reports, demonstrate the importance of protein-protein interactions in the process of DNA repair.
Mol Cell Biol 1995 Sep
PMID:Functional differences and interactions among the putative RecA homologs Rad51, Rad55, and Rad57. 765 2

Mutation in the REC2 gene of Ustilago maydis leads to defects in DNA repair, recombination, and meiosis. Analysis of the primary sequence of the Rec2 protein reveals a region with significant homology to bacterial RecA protein and to the yeast recombination proteins Dmc1, Rad51, and Rad57. This homologous region in the U. maydis Rec2 protein was found to be functionally sensitive to mutation, lending support to the hypothesis that Rec2 has a functional RecA-like domain essential for activity in recombination and repair. Homologous recombination between plasmid and chromosomal DNA sequences is reduced substantially in the rec2 mutant following transformation. The frequency can be restored to a level approaching, but not exceeding, that observed in the wild-type strain if transformation is performed with cells containing multiple copies of REC2.
Mol Cell Biol 1994 Sep
PMID:Structure of REC2, a recombinational repair gene of Ustilago maydis, and its function in homologous recombination between plasmid and chromosomal sequences. 806 60

The mei-3 gene of Neurospora crassa encodes a homolog of the Escherichia coli RecA and Saccharomyces cerevisiae Rad51 proteins, which are required for recombination and repair of DNA double-strand breaks. To determine the molecular function of MEI3 protein, anti-MEI3 antibody was prepared and used in Western blot analysis. The antibody cross-reacted only with crude extracts prepared from perithecia, the fruiting bodies of Neurospora. The molecular weight of the MEI3 protein was estimated to be 38 kDa. Transformation experiments showed that a DNA fragment longer than previously reported was needed to complement the mei-3 mutation. On sequencing cDNA and genomic DNA, one open reading frame (ORF) was found, which consists of three exons interrupted by two small introns. This ORF encoded a MEI3 protein of 353 amino acids, and the inferred MW of 38 kDa is in good agreement with the results from Western blot analysis. Comparisons of MEI3 with other Rad51 homologs indicated that MEI3 protein contains the two conserved core domains (I and II) generally observed in Rad51 homologs in eukaryotes. Northern blot analysis showed that expression of mei-3 was raised remarkably after UV-irradiation or methyl methanesulfonate (MMS)-treatment. The transcript size was 1.6 kb and this was also larger than was reported previously.
Mol Gen Genet 1995 Dec 10
PMID:Identification and expression of the Neurospora crassa mei-3 gene which encodes a protein homologous to Rad51 of Saccharomyces cerevisiae. 855 49

The mouse Rad51 gene is a mammalian homologue of the Escherichia coli recA and yeast RAD51 genes, both of which are involved in homologous recombination and DNA repair in mitosis and meiosis. The expression of mouse Rad51 mRNA was examined in synchronized mouse m5S cells. The Rad51 transcript was observed from late G1 phase through to M phase. During the period of late G1-S-G2, the RAD51 proteins were observed exclusively in nuclei. Activation by mitogens of T cell and B cell proliferation in spleen induced the expression of Rad51 mRNA. By immunohistochemical analyses, in mouse RAD51 protein was detected in proliferating cells: spermatogonia in testis, immature T cells in thymus, germinal center cells of the secondary lymphatic nodules of spleen and intestine, follicle cells in ovary and epithelial cells in uterus and intestine. It was also expressed in spermatocytes during early and mid-prophase of meiosis and in resting oocytes before maturation. Thus, mouse Rad51 expression is closely related to the state of cell proliferation and is presumably involved in DNA repair coupled with DNA replication, as well as in meiotic DNA recombination in spermatocytes.
Mol Gen Genet 1996 Apr 24
PMID:Cell cycle-dependent expression of the mouse Rad51 gene in proliferating cells. 862 40

To understand the role of the Rhp51 protein in Schizosaccharomyces pombe, we examined the phenotypes of the null mutant for the rhp51+ gene. Unlike Saccharomyces cerevisiae rad51 mutants, S. pombe rhp51 mutants (rhp51delta cells) displayed slow growth and heterogeneity in cell size, indicating perturbation of the cell cycle. Furthermore, many aberrant nuclear structures found in 4',6'-diamidino-2-phenylindole (DAPI)-stained rhp51delta cells and the caffeine hypersensitivity of the mutant cells suggested an involvement of the Rhp51 protein in normal chromosome segregation. These data suggested that the Rhp51 proteins were required for normal cell growth as well as a DNA repair pathway. Moreover, rhp51delta mutants showed a considerable sensitivity to ultraviolet (UV) light-irradiation as well as methyl methanesulfonate (MMS) treatment, indicating that the Rhp51 proteins are involved in both the active excision mechanism of UV-induced DNA damage and recombinational repair in S. pombe. Taken together, we suggest that the role(s) of the Rhp51 protein in S. pombe may be different from those of Rad51 in S. cerevisiae.
Biochem Mol Biol Int 1995 Oct
PMID:Evidences for possible involvement of Rhp51 protein in mitotic events including chromosome segregation. 867 16

Suppressors of the methyl methanesulfonate sensitivity of Saccharomyces cerevisiae diploids lacking the Srs2 helicase turned out to contain semidominant mutations in Rad5l, a homolog of the bacterial RecA protein. The nature of these mutations was determined by direct sequencing. The 26 mutations characterized were single base substitutions leading to amino acid replacements at 18 different sites. The great majority of these sites (75%) are conserved in the family of RecA-like proteins, and 10 of them affect sites corresponding to amino acids in RecA that are probably directly involved in ATP reactions, binding, and/or hydrolysis. Six mutations are in domains thought to be involved in interaction between monomers; they may also affect ATP reactions. By themselves, all the alleles confer a rad5l null phenotype. When heterozygous, however, they are, to varying degrees, negative semidominant for radiation sensitivity; presumably the mutant proteins are coassembled with wild-type Rad51 and poison the resulting nucleofilaments or recombination complexes. This negative effect is partially suppressed by an SRS2 deletion, which supports the hypothesis that Srs2 reverses recombination structures that contain either mutated proteins or numerous DNA lesions.
Mol Cell Biol 1996 Sep
PMID:Semidominant mutations in the yeast Rad51 protein and their relationships with the Srs2 helicase. 875 36

Protein sequences with similarities to Escherichia coli RecA were compared across the major kingdoms of eubacteria, archaebacteria, and eukaryotes. The archaeal sequences branch monophyletically and are most closely related to the eukaryotic paralogous Rad51 and Dmc1 groups. A multiple alignment of the sequences suggests a modular structure of RecA-like proteins consisting of distinct segments, some of which are conserved only within subgroups of sequences. The eukaryotic and archaeal sequences share an N-terminal domain which may play a role in interactions with other factors and nucleic acids. Several positions in the alignment blocks are highly conserved within the eubacteria as one group and within the eukaryotes and archaebacteria as a second group, but compared between the groups these positions display nonconservative amino acid substitutions. Conservation within the RecA-like core domain identifies possible key residues involved in ATP-induced conformational changes. We propose that RecA-like proteins derive evolutionarily from an assortment of independent domains and that the functional homologs of RecA in noneubacteria comprise an array of RecA-like proteins acting in series or cooperatively.
J Mol Evol 1997 May
PMID:Evolutionary comparisons of RecA-like proteins across all major kingdoms of living organisms. 911 77

An E. coli RecA and yeast RAD51 homolog from Aspergillus nidulans, radA, has been cloned by screening genomic and cDNA libraries with a PCR-amplified probe. This probe was generated using primers carrying the conserved sequences of eukaryotic RecA homologs. The deduced amino acid sequence revealed two conserved Walker-A and -B type nucleotide-binding domains and exhibited 88%, 60%, and 53% identity with Mei-3 of Neurospora crassa, rhp51+ of Schizosaccharomyces pombe, and Rad51 of Saccharomyces cerevisiae, respectively. radA null mutants constructed by replacing the whole coding region with a selection marker showed high methyl methanesulfonate (MMS) sensitivity. Heterozygous diploids of radA disruptant with the uvsC114 mutant failed to complement with respect to MMS-sensitivity, indicating that radA is an allele of uvsC. In selecting spontaneous forward selenate resistant mutations, mutator effects were observed in radA null mutants similarly to those shown in uvsC114 mutant strains.
Mol Cells 1997 Apr 30
PMID:Cloning of an E. coli RecA and yeast RAD51 homolog, radA, an allele of the uvsC in Aspergillus nidulans and its mutator effects. 916 46


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