Interaction of the yeast Pso5/Rad16 and Sgs1 proteins: influences on DNA repair and aging.
The interaction trap method was used to isolate putative binding partners of Rad16/Pso5, a protein responsible for repair of silent DNA. One of the interactors found was Sgs1, a DNA helicase influencing the life span of Saccharomyces cerevisiae, with homology to the human BLM, WRN and RECQL4 proteins. Using the same fusion proteins from the two-hybrid screening, we show evidence that both proteins also interact in vitro. We tested isogenic strains, containing mutant alleles of the two genes in single and double mutant combination, for phenotypic similarity. Life span in sgs1Delta single and sgs1Delta rad16Delta double mutants is about 40% of that of WT, and the rad16/pso5Delta single mutant also had its life span reduced to 75%. Sensitivity to different mutagens, whose lesions are poorly repaired in rad16/pso5Delta mutants, was tested in sgs1Delta mutants. The sgs1Delta conferred sensitivity to MMS, H2O2 and was moderately sensitive to UV(254nm) (UVC) and 4-NQO. An epistatic interaction between rad16 and sgs1 mutations after UVC, 4-NQO and H2O2 was observed. Moreover, we found that in a top3 background, functional Sgs1p and Rad16p apparently channel MMS, 4-NQO and H2O2 induced lesions into aberrant DNA repair. Our results demonstrate that Sgs1 is not only involved in genome stability, somatic recombination and aging, but is also implicated, together with Rad16/Pso5, in the repair of specific DNA damage.
Saffi
J
J
Centro de Biotecnologia and Depto. de Biofísica, UFRGS, Av. Bento Gonçalves, 9500 Prédio, 43421 Campus do Vale, 91501-970, RS, Porto Alegre, Brazil.
Feldmann
H
H
Winnacker
E L
EL
Henriques
J A
JA
D000251:Adenosine Triphosphatases; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair / Q000235:genetics; D004271:DNA, Fungal / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005800:Genes, Fungal; D006801:Humans; D009153:Mutagens / Q000633:toxicity; D009154:Mutation; D053484:RecQ Helicases; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D020798:Two-Hybrid System Techniques; D014466:Ultraviolet Rays / Q000009:adverse effects
D004271:DNA, Fungal; D005656:Fungal Proteins; D009153:Mutagens; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D000251:Adenosine Triphosphatases; C090472:SGS1 protein, S cerevisiae; C075467:RAD16 protein, S cerevisiae; D004265:DNA Helicases; D053484:RecQ Helicases