Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

RAD54 is an important member of the RAD52 group of genes that carry out recombinational repair of DNA damage in the yeast Saccharomyces cerevisiae. Rad54 protein is a member of the Snf2/Swi2 protein family of DNA-dependent/stimulated ATPases, and its ATPase activity is crucial for Rad54 protein function. Rad54 protein and Rad54-K341R, a mutant protein defective in the Walker A box ATP-binding fold, were fused to glutathione-S-transferase (GST) and purified to near homogeneity. In vivo, GST-Rad54 protein carried out the functions required for methyl methanesulfonate sulfate (MMS), UV, and DSB repair. In vitro, GST-Rad54 protein exhibited dsDNA-specific ATPase activity. Rad54 protein stimulated Rad51/Rpa-mediated DNA strand exchange by specifically increasing the kinetics of joint molecule formation. This stimulation was accompanied by a concurrent increase in the formation of heteroduplex DNA. Our results suggest that Rad54 protein interacts specifically with established Rad51 nucleoprotein filaments before homology search on the duplex DNA and heteroduplex DNA formation. Rad54 protein did not stimulate DNA strand exchange by increasing presynaptic complex formation. We conclude that Rad54 protein acts during the synaptic phase of DNA strand exchange and after the formation of presynaptic Rad51 protein-ssDNA filaments.
J Mol Biol 2001 Apr 13
PMID:Rad54 protein stimulates heteroduplex DNA formation in the synaptic phase of DNA strand exchange via specific interactions with the presynaptic Rad51 nucleoprotein filament. 1129 36

Targeted gene repair directed by chimeric RNA/DNA oligonucleotides has proven successful in eukaryotic cells including animal and plant models. In many cases, however, there has been a disparity in the levels of gene correction or frequency. While the delivery of these chimera into the nucleus and the long-term stability or purity of these molecules may contribute to this variability, understanding the molecular regulation of conversion is the key to improving or stabilizing frequency. To this end, we have identified genes that control targeted repair, using the genetically tractable organism, Saccharomyces cerevisae and a bank of yeast mutants. Results from experiments in cell-free extracts focused our attention on RAD52, RAD1 and RAD59 as central regulatory factors. RAD1 and RAD59 appear to be required for high levels of conversion whereas RAD52 appears to act, surprisingly, in a suppressive fashion. Results from the in vitro experiments were translated into targeting experiments in vivo. Here, mutations in a fusion construct, containing a marker gene, were converted to wild type, evidenced by the expression of green fluorescence in converted cells. Because the repaired fusion gene contains a corrected neomycin sequence, cells were subsequently placed under G418 selection and conversion confirmed at the genetic level. Taken together, these results establish, for the first time, genes that participate in the regulation of targeted gene repair and provide a novel system for evaluating true frequencies of correction. Importantly, this system enables visualization of corrected (green) and uncorrected (clear) cells enabling measurements of conversion in real time.
Mol Microbiol 2001 May
PMID:In vitro and in vivo nucleotide exchange directed by chimeric RNA/DNA oligonucleotides in Saccharomyces cerevisae. 1140 93

The removal of oxidative base damage from the genome of Saccharomyces cerevisiae is thought to occur primarily via the base excision repair (BER) pathway in a process initiated by several DNA N-glycosylase/AP lyases. We have found that yeast strains containing simultaneous multiple disruptions of BER genes are not hypersensitive to killing by oxidizing agents, but exhibit a spontaneous hyperrecombinogenic (hyper-rec) and mutator phenotype. The hyper-rec and mutator phenotypes are further enhanced by elimination of the nucleotide excision repair (NER) pathway. Furthermore, elimination of either the lesion bypass (REV3-dependent) or recombination (RAD52-dependent) pathway results in a further, specific enhancement of the hyper-rec or mutator phenotypes, respectively. Sensitivity (cell killing) to oxidizing agents is not observed unless multiple pathways are eliminated simultaneously. These data suggest that the BER, NER, recombination, and lesion bypass pathways have overlapping specificities in the removal of, or tolerance to, exogenous or spontaneous oxidative DNA damage in S. cerevisiae. Our results also suggest a physiological role for the AP lyase activity of certain BER N-glycosylases in vivo.
Prog Nucleic Acid Res Mol Biol 2001
PMID:Yeast base excision repair: interconnections and networks. 1155 5

Recombinational repair was first detected in budding yeast Saccharomyces cerevisiae and was also studied in fission yeast Schizosaccharomyces pombe over the recent decade. The discovery of Sch. pombe homologs of the S. cerevisiae RAD52 genes made it possible not only to identify and to clone their vertebrate counterparts, but also to study in detail the role of DNA recombination in certain cell processes. For instance, recombinational repair was shown to play a greater role in maintaining genome integrity in fission yeast and in vertebrates compared with S. cerevisiae. The present state of the problem of recombinational double-strand break repair in fission yeast is considered with a focus on comparisons between Sch. pombe and higher eukaryotes. The role of double-strand break repair in maintaining genome stability is discussed.
Mol Biol (Mosk)
PMID:[Recombinational repair in Schizosaccharomyces pombe: role in maintaining genomic integrity]. 1160 27

Rap1p, the major telomere repeat binding protein in yeast, has been implicated in both de novo telomere formation and telomere length regulation. To characterize the role of Rap1p in these processes in more detail, we studied the generation of telomeres in vivo from linear DNA substrates containing defined arrays of Rap1p binding sites. Consistent with previous work, our results indicate that synthetic Rap1p binding sites within the internal half of a telomeric array are recognized as an integral part of the telomere complex in an orientation-independent manner that is largely insensitive to the precise spacing between adjacent sites. By extending the lengths of these constructs, we found that several different Rap1p site arrays could never be found at the very distal end of a telomere, even when correctly oriented. Instead, these synthetic arrays were always followed by a short ( approximately 100-bp) "cap" of genuine TG repeat sequence, indicating a remarkably strict sequence requirement for an end-specific function(s) of the telomere. Despite this fact, even misoriented Rap1p site arrays promote telomere formation when they are placed at the distal end of a telomere-healing substrate, provided that at least a single correctly oriented site is present within the array. Surprisingly, these heterogeneous arrays of Rap1p binding sites generate telomeres through a RAD52-dependent fusion resolution reaction that results in an inversion of the original array. Our results provide new insights into the nature of telomere end capping and reveal one way by which recombination can resolve a defect in this process.
Mol Cell Biol 2001 Dec
PMID:Telomere formation by rap1p binding site arrays reveals end-specific length regulation requirements and active telomeric recombination. 1168 1

A series of yeast mutants were isolated that are sensitive to killing by the monofunctional DNA-alkylating agent methyl methanesulfonate (MMS) but not by UV or X-radiation. We have cloned and characterized one of the corresponding genes, MMS1, and show that the mms1 Delta mutant is dramatically sensitive to killing by MMS and mildly sensitive to UV radiation. mms1 Delta mutants display an elevated level of spontaneous DNA damage and genomic instability. Furthermore, the mms1 Delta cells are sensitive to killing by conditions that induce replication-dependent double-strand breaks, such as treatment with camptothecin, and incubation of a cdc2-2 strain at the restrictive temperature. rad52 Delta is epistatic to mms1 Delta for MMS and camptothecin sensitivity, indicating that Mms1 acts in concert with Rad52. However, unlike mutants of the RAD52 group, mms1 Delta cells are not sensitive to gamma-rays, which induce double-strand breaks independently of DNA replication. Together these results suggest a role for an Mms1-dependent, Rad52-mediated, pathway in protecting cells against replication-dependent DNA damage.
Mol Genet Genomics 2002 Jan
PMID:MMS1 protects against replication-dependent DNA damage in Saccharomyces cerevisiae. 1181 Feb 60

We performed genetic association studies in a population-based breast cancer case-control study analysing polymorphisms in genes involved in homologous recombination (NBS1, RAD52, RAD51, XRCC2 and XRCC3) and non-homologous end-joining (KU70/80 and LIG4). These DNA double-strand break repair genes are candidates for breast cancer susceptibility. Genotype results were available for up to 2205 cases and 1826 controls. In the homologous recombination (HR) pathway, genotype frequencies differed between cases and controls for two polymorphisms in XRCC3; T241M (P=0.015) and IVS5 A>G at nt 17893 (P=0.008). Homozygous carriers of M241 were associated with an increased risk [odds ratio (OR) MM versus TT=1.3 (95% confidence interval (CI) 1.1-1.6)], while the rare allele of IVS5A>G was associated with a dominant protective effect [OR AG versus AA=0.8 (0.7-0.9)]. The association of a rare variant in XRCC2 (R188H) was marginally significant [P=0.07; OR HH versus RR=2.6 (1.0-6.7)]. In the non-homologous end-joining (NHEJ) pathway, a polymorphism in LIG4 (T>C at nt 1977) was associated with a decrease in breast cancer risk [P=0.09; OR CC versus TT=0.7 (0.4-1.0)]. No significant association was found for 12 other polymorphisms in the other genes studied. For XRCC3, we found evidence for four common haplotypes and four rarer ones that appear to have arisen by recombination. Two haplotypes, AGC and GGC, were associated with non-significant reductions in breast cancer risk, and the rare GAT haplotype was associated with a significantly increased risk. These data provide some evidence that variants in XRCC2 and LIG4 alter breast cancer risk, together with stronger evidence that variants of XRCC3 are associated with risk. If these results can be confirmed, understanding the functional basis should improve our understanding of the role of DNA repair in breast carcinogenesis.
Hum Mol Genet 2002 Jun 01
PMID:Variants in DNA double-strand break repair genes and breast cancer susceptibility. 1202 82

Repair of double-strand breaks by gene conversions between homologous sequences located on different Saccharomyces cerevisiae chromosomes or plasmids requires RAD51. When repair occurs between inverted repeats of the same plasmid, both RAD51-dependent and RAD51-independent repairs are found. Completion of RAD51-independent plasmid repair events requires RAD52, RAD50, RAD59, TID1 (RDH54), and SRS2 and appears to involve break-induced replication coupled to single-strand annealing. Surprisingly, RAD51-independent recombination requires much less homology (30 bp) for strand invasion than does RAD51-dependent repair (approximately 100 bp); in fact, the presence of Rad51p impairs recombination with short homology. The differences between the RAD51- and RAD50/RAD59-dependent pathways account for the distinct ways that two different recombination processes maintain yeast telomeres in the absence of telomerase.
Mol Cell Biol 2002 Sep
PMID:Characterization of RAD51-independent break-induced replication that acts preferentially with short homologous sequences. 1219 38

Rad54 protein is a member of the Swi2/Snf2-like family of DNA-dependent/stimulated ATPases that dissociate and remodel protein complexes on dsDNA. Rad54 functions in the recombinational DNA repair (RAD52) pathway. Here we show that Rad54 protein dissociates Rad51 from nucleoprotein filaments formed on dsDNA. Addition of Rad54 protein overcomes inhibition of DNA strand exchange by Rad51 protein bound to substrate dsDNA. Species preference in the Rad51 dissociation and DNA strand exchange assays underlines the importance of specific Rad54-Rad51 protein interactions. Rad51 protein is unable to release dsDNA upon ATP hydrolysis, leaving it stuck on the heteroduplex DNA product after DNA strand exchange. We suggest that Rad54 protein is involved in the turnover of Rad51-dsDNA filaments.
Mol Cell 2002 Nov
PMID:Rad54, a Swi2/Snf2-like recombinational repair protein, disassembles Rad51:dsDNA filaments. 1245 24

The process of homologous recombination is a major DNA repair pathway that operates on DNA double-strand breaks, and possibly other kinds of DNA lesions, to promote error-free repair. Central to the process of homologous recombination are the RAD52 group genes (RAD50, RAD51, RAD52, RAD54, RDH54/TID1, RAD55, RAD57, RAD59, MRE11, and XRS2), most of which were identified by their requirement for the repair of ionizing-radiation-induced DNA damage in Saccharomyces cerevisiae. The Rad52 group proteins are highly conserved among eukaryotes, and Rad51, Mre11, and Rad50 are also conserved in prokaryotes and archaea. Recent studies showing defects in homologous recombination and double-strand break repair in several human cancer-prone syndromes have emphasized the importance of this repair pathway in maintaining genome integrity. Although sensitivity to ionizing radiation is a universal feature of rad52 group mutants, the mutants show considerable heterogeneity in different assays for recombinational repair of double-strand breaks and spontaneous mitotic recombination. Herein, I provide an overview of recent biochemical and structural analyses of the Rad52 group proteins and discuss how this information can be incorporated into genetic studies of recombination.
Microbiol Mol Biol Rev 2002 Dec
PMID:Role of RAD52 epistasis group genes in homologous recombination and double-strand break repair. 1245 86


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>