Efficient repair of large DNA loops in Saccharomyces cerevisiae

UMMS Affiliation

Graduate School of Biomedical Sciences; Department of Biochemistry and Molecular Pharmacology

Publication Date


Document Type



Life Sciences | Medicine and Health Sciences


Small looped mispairs are efficiently corrected by mismatch repair. The situation with larger loops is less clear. Repair activity on large loops has been reported as anywhere from very low to quite efficient. There is also uncertainty about how many loop repair activities exist and whether any are conserved. To help address these issues, we studied large loop repair in Saccharomyces cerevisiae using in vivo and in vitro assays. Transformation of heteroduplexes containing 1, 16 or 38 nt loops led to >90% repair for all three substrates. Repair of the 38 base loop occurred independently of mutations in key genes for mismatch repair (MR) and nucleotide excision repair (NER), unlike other reported loop repair functions in yeast. Correction of the 16 base loop was mostly independent of MR, indicating that large loop repair predominates for this size heterology. Similarities between mammalian and yeast large loop repair were suggested by the inhibitory effects of loop secondary structure and by the role of defined nicks on the relative proportions of loop removal and loop retention products. These observations indicate a robust large loop repair pathway in yeast, distinct from MR and NER, and conserved in mammals.

DOI of Published Version



Nucleic Acids Res. 2001 Oct 15;29(20):4134-43.

Journal/Book/Conference Title

Nucleic acids research

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Link to article in PubMed

PubMed ID