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

It was found that yeast cells contain an endonuclease specific for apurinic sites in DNA which has no effect on DNA with normal strands or on strands with alkylated sites. The enzyme activity was studied in the RAD strain and in rad 6, rad 18-2 and rad 21 mutants, all very sensitive to MMS, as compared to the wild type. The level of endonuclease activity does not differ much between the tested strains, regardless of their differences in susceptibility to MMS. The enzyme activity is not induced by pretreatment of the cells with this mutagen.
Mol Gen Genet 1977 Jul 20
PMID:Endonuclease for apurinic sites in yeast. Comparison of the enzyme activity in the wild type and in rad mutants of Saccharomyces cerevisiae to MNS. 19 92

A mutant of Saccharomyces cerevisiae has been isolated which, though exhibiting a normal response to nuclear genetic damage by ultraviolet light (UV), is more sensitive than its wild type specifically in the production of the cytoplasmic (rho-) mutation by this agent. Some of the features of this mutation which has been designated uvsrho 5 are: i) The mutation is recessive, it exhibits a Mendelian, and hence presumably nuclear, pattern of segregation, but manifests its effects specifically and pleiotropically on mitochondrial functions. ii) Mutant cells resemble their wild type parents in a) growth characteristics on glucose; b) in their UV induced dose response to lethality or nuclear mutation and c) the ability of their mitochondrial genome, upon mating with appropriate testers, of transmitting and recombining various markers, albeit with enhanced efficiency. Similarly, d) they are able to modulate the expression of mitochondrial mutagenesis by ethidium bromide. Thus their mitochondrial DNA appears genetically as competent as that of the wild type. iii) Mutant cells differ from their wild type parents in a) growth characteristics on glycerol; b) susceptibility to induction of the mitochondrial (rho-) mutation by various mutagens, in that the rate of spontaneous mutation is slightly and that by UV is significantly enhanced, whild that by ethidium bromide is greatly diminished. Conversely, c) modulating influences resulting in the repair of initial damage are diminished fro UV and stimulated in the case of Berenil. iv) The amount of mitochondrial DNA per cell appears elevated in the mutant, relative to wild type, and its rate of degradation subsequent to a mutagenic exposure to either UV or ethidium bromide is diminished. v) A self-consistent scheme to account for this and all other information so far available for the induction and modulation of the (rho-) mutation is presented. In a previous study it was shown that some nuclear mutants of Saccharomyces cerevisiae, more sensitive to lethal damage induced by ultraviolet light (rad) than their parent wild type (RAD), also exhibit a concomitant modification in sensitivity to both nuclear and cytoplasmic genetic damage (Moustacchi, 1971). However, another class of rad mutants respond to the induction of the cytoplasmic "petite" also designated as rho- (or rho-) mutation by UV in a manner indistinguishable from that of the RAD strain. One possible interpretation of this last observation is that some of the steps in the expression of the UV damage on mitochondrial (mt)DNA may be governed by other nuclear and cytoplasmic genetic determinants, the products of which may then act specifically on mitochondrial lesions. If this assumption is correct, it should be possible to find mutants with a normal response to nuclear damage but specifically UV-sensitive towards induction of (rho-)...
Mol Gen Genet 1976 Nov 17
PMID:A novel class of Saccharomyces cerevisiae mutants specifically UV-sensitive to "petite" induction. 79 62

Psoralen photoreaction with DNA produces interstrand crosslinks, which require the activity of excision and recombinational pathways for repair. Yeast replicating plasmids, carrying the HIS3, TRP1, and URA3 genes, were photoreacted with psoralen in vitro and transfected into Saccharomyces cerevisiae cells. Repair was assayed as the relative transformation efficiency. A recombination-deficient rad52 strain was the least efficient in the repair of psoralen-damaged plasmids; excision repair-deficient rad1 and rad3 strains had repair efficiencies intermediate between those of rad52 and RAD cells. The level of repair also depended on the conditions of transformant selection; repair was more efficient in medium lacking tryptophan than in medium from which either histidine or uracil was omitted. The plasmid repair differential between these selective media was greatest in rad1 cells, and depended on RAD52. Plasmid-chromosome recombination was stimulated by psoralen damage, and required RAD52 function. Chromosome to plasmid gene conversion was seen most frequently at the HIS3 locus. In RAD and rad3 cells, the majority of the conversions were associated with plasmid integration, while in rad1 cells most were non-crossover events. Plasmid to chromosome gene conversion was observed most frequently at the TRP1 locus, and was accompanied by plasmid loss.
Mol Gen Genet 1992 Dec
PMID:Differential repair and recombination of psoralen damaged plasmid DNA in Saccharomyces cerevisiae. 149 54

Multiple genes (many of which are designated RAD (for radiation resistance)) are required for cellular responses to DNA damage in the yeast Saccharomyces cerevisiae. In recent years a number of these genes have been cloned and sequenced and in some cases their polypeptide products have been purified and characterized biochemically. These studies are beginning to yield clues about the possible nature of the multiple biochemical pathways for DNA-damage processing in yeast.
Mol Microbiol 1991 Oct
PMID:Yeast genes involved in DNA-repair processes: new looks on old faces. 166 93

RNR2 encodes the small subunit of ribonucleotide reductase, the enzyme that catalyzes the first step in the pathway for the production of deoxyribonucleotides needed for DNA synthesis. RNR2 is a member of a group of genes whose activities are cell cycle regulated and that are transcriptionally induced in response to the stress of DNA damage. An RNR2-lacZ fusion was used to further characterize the regulation of RNR2 and the pathway responsible for its response to DNA damage. beta-Galactosidase activity in yeast strains containing the RNR2-lacZ fusion was inducible in response to DNA-damaging agents (UV light, 4-nitroquinoline-1-oxide [4-NQO], and methyl methanesulfonate [MMS]) and agents that block DNA replication (hydroxyurea [HU] and methotrexate) but not heat shock. When MATa cells were arrested in G1 by alpha-factor, RNR2 mRNA was still inducible by DNA damage, indicating that the observed induction can occur outside of S phase. In addition, RNR2 induction was not blocked by the presence of cycloheximide and is therefore likely to be independent of protein synthesis. A mutation, rnr2-314, was found to confer hypersensitivity to HU and increased sensitivity to MMS. In rnr2-314 mutant strains, the DNA damage stress response was found to be partially constitutive as well as hypersensitive to induction by HU but not MMS. The induction properties of RNR2 were examined in a rad4-2 mutant background; in this genetic background, RNR2 was hypersensitive to induction by 4-NQO but not MMS. Induction of the RNR2-lacZ fusion in a RAD(+) strain in response to 4-NQO was not enhanced by the presence of an equal number of rad4-2 cells that lacked the fusion, implying that the DNA damage stress response in cell autonomous.
Mol Cell Biol 1989 Nov
PMID:DNA damage induction of ribonucleotide reductase. 251 80

The roles of the RAD genes of Saccharomyces cerevisiae in the regulation of transcription of two DNA damage responsive (DDR) genes were investigated by examining the levels of the DDRA2 and DDR48 transcripts in different rad mutants after exposure to two different DNA damaging agents. Strains carrying mutations in either the RAD3, RAD6 or RAD52 genes were treated with increasing concentrations of 4-nitroquinoline-1-oxide (NQO) or N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and the DDR transcript levels were determined by Northern hybridization analysis. Our results indicate that the RAD3 gene is required for DDRA2 transcript production following NQO or MNNG treatments. Strains carrying mutations in either the RAD6 or RAD52 genes show an increased level of DDRA2 transcript in undamaged cells. However, the rad6 and rad52 mutants show a normal dose-dependent increase in DDRA2 transcript levels after NQO or MNNG exposure. The DDR48 gene appears to be regulated differently from DDRA2 in that this gene is induced in rad3 cells after damaging treatment but transcript induction is severely reduced in both rad6 and rad52 mutant strains. Although the rad mutations influence the kinetics of transcript accumulation, these effects do not account for the altered dose responses of the DDRA2 and DDR48 genes. Our results also demonstrate that the regulation of DDRA2 and DDR48 transcript levels by heat shock treatment is affected less severely in the different rad strains, a result which suggests that the RAD genes play an indirect role in DDR gene control.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Gen Genet 1986 Nov
PMID:Transcriptional regulation of DNA damage responsive (DDR) genes in different rad mutant strains of Saccharomyces cerevisiae. 310 Sep 12

In contrast to other Saccharomyces cerevisiae RAD genes involved in nucleotide excision repair of DNA, the RAD4 gene could not be isolated by screening a yeast genomic library for recombinant plasmids which complement the UV sensitivity of rad4 mutants (Pure et al., J. Mol. Biol. 183:31-42, 1985). We therefore attempted to walk to RAD4 from the neighboring SPT2 gene and obtained an integrating derivative of a plasmid isolated by Roeder et al. (Mol. Cell. Biol. 5:1543-1553, 1985) which contains a 4-kilobase fragment of yeast DNA including a mutant allele of SPT2. When integrated into several different rad4 mutant strains, this plasmid (pR169) complements UV sensitivity at a frequency of approximately 10%. However, a centromeric plasmid containing rescued sequences which include flanking yeast DNA no longer complements the phenotype of rad4 mutants. Complementing activity was restored by in vivo repair of a defined gap in the centromeric plasmid. The repaired plasmid fully complements the UV sensitivity of all rad4 mutants tested when isolated directly from yeast cells, but when this plasmid is propagated in Escherichia coli complementing activity is lost. We have mapped the physical location of the RAD4 gene by insertional mutagenesis and by transcript mapping. The gene is approximately 2.3 kilobases in size and is located immediately upstream of the SPT2 gene. Both genes are transcribed in the same direction. RAD4 is not an essential gene, and no increased transcription of this gene is observed in cells exposed to the DNA-damaging agent 4-nitroquinoline-1-oxide. The site of inactivation of RAD4 in a particular plasmid propagated in E. coli was localized to a 100-base-pair region by gene disruption and gap repair experiments. In addition, we have identified the approximate locations of the chromosomal rad4-2, rad4-3, and rad4-4 mutations.
Mol Cell Biol 1987 Mar
PMID:RAD4 gene of Saccharomyces cerevisiae: molecular cloning and partial characterization of a gene that is inactivated in Escherichia coli. 355 Apr 31

The survival of plasmid YRp12 treated in vitro with ultraviolet- or gamma-radiation, or with restriction endonucleases, has been used to investigate in vivo RAD gene activity in Saccharomyces cerevisiae. Yields of pyrimidine dimers or single and double strand breaks in plasmid DNA were assayed by physical methods. The biological effects of these damages were assayed by transformation of wild-type cells and rad mutants from each of the major groups of radiosensitive mutants. After UV-irradiation plasmid survival depended qualitatively on the same host functions that are needed for cellular survival. After gamma-irradiation no such correspondence was found. Apart from a RAD52-dependent stimulation of transformation efficiency at low doses, other host repair functions had little effect. Stimulation of transformation corresponded with the production of double- but not single-strand breaks in plasmid sequences homologous with the yeast genome and may be linked with a transient increase in mitotic stability. More generally these data also show that transformation events using the LiCl protocol may entail the uptake of a very low number of plasmid molecules per cell over a 10-fold range of DNA concentrations.
Mol Gen Genet 1985
PMID:The use of plasmid DNA to probe DNA repair functions in the yeast Saccharomyces cerevisiae. 390 37

Ultraviolet (UV) mutagenesis in a plasmid-borne Saccharomyces cerevisiae tRNA gene (SUP4-o) occurs preferentially at sites where the pyrimidine in the base pair is part of a dipyrimidine sequence on the transcribed strand. In this study, we examined whether excision repair, or strand identity with respect to DNA replication, influences this strand bias. The specificity of UV mutagenesis was determined for a wild type (RAD) strain and an isogenic excision repair-deficient (rad1) derivative, each carrying SUP4-o on the vector YCpMP2, or another vector (YCpJA1) that differed only in the orientation of SUP4-o with respect to a unique origin of replication. Most (> or = 90%) of the SUP4-o mutations induced by UV in these strains were single base pair substitutions, predominantly (> 87%) transitions. The rad1 defect and inversion of SUP4-o in the RAD strain eliminated the strand preference, whereas inversion of SUP4-o in the rad1 strain caused it to reappear. Both conditions also altered the distribution of frequently mutated sites and the relative fraction of transitions at TT sequences. These results suggest that excision repair and gene orientation can be important determinants for the strand and site specificities of UV mutagenesis in SUP4-o on YCpMP2 and YCpJA1. We consider several possible explanations for our observations, including potential roles for transcription by RNA polymerase II, sequence context effects on the efficiency of excision repair, and inherent differences in strand mutability or translesion synthesis by the leading and lagging strand DNA replication complexes.
Environ Mol Mutagen 1995
PMID:Excision repair and gene orientation modulate the strand specificity of UV mutagenesis in a plasmid-borne yeast tRNA gene. 787 22

A screening method for mutants of Arabidopsis thaliana hypersensitive to gamma-radiation has been devised. Plants grown from ethyl methanesulfonate (EMS)-treated seeds were irradiated at the seedling stage, which is highly radiosensitive due to extensive cell division. Severe growth inhibition of mutant plants by a gamma-ray dose which only slightly affects wild-type plants was the selective criterion. Twelve true-breeding hypersensitive lines were isolated from a total of 3394 screened plants. Genetic analysis of five of the lines revealed five new genes, designated RAD1-RAD5. These Arabidopsis RAD mutants are phenotypically similar to mutants in the RAD52 epistasis group of Saccharomyces cerevisiae, which are highly sensitive to ionizing radiation but not hypersensitive to UV light. One possibility is that the Arabidopsis mutants are defective in a nonhomologous or illegitimate recombination mechanism used by plants for repair of chromosome breaks.
Mol Gen Genet 1994 Jun 15
PMID:Isolation of Arabidopsis thaliana mutants hypersensitive to gamma radiation. 802 82


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