Abstract
Nucleotide excision repair (NER) is the primary pathway for the removal of DNA adducts that distort the double helix. In the yeast Saccharomyces cerevisiae the RAD6 epistasis group defines a more poorly characterized set of DNA damage response pathways, believed to be distinct from NER. Here we show that the elimination of the DNA minor groove adducts formed by an important class of anticancer antibiotic (CC-1065 family) requires NER factors in S. cerevisiae. We also demonstrate that the elimination of this class of minor groove adduct from the active MFA2 gene depends upon functional Rad18 and Rad6. This is most clear for the repair of adducts on the transcribed strand, where an absolute requirement for Rad6 and Rad18 was seen. Further experiments revealed that a specific RAD6-RAD18-controlled subpathway, the RAD5 branch, mediates these events. Cells disrupted for rad5 are highly sensitive to this minor groove binding agent, and rad5 cells exhibit an in vivo adduct elimination defect indistinguishable from that seen in rad6 and rad18 cells as well as in NER-defective cells. Our results indicate that the RAD5 subpathway may interact with NER factors during the repair of certain DNA adducts.
Highlights
Nucleotide excision repair (NER)1 is the principal DNA repair pathway acting on bulky DNA lesions, such as those formed by ultraviolet light and cisplatin, in both prokaryotes and eukaryotes [1]
NER-defective Yeast Cells Are Sensitive to the CC-1065 Family of Drugs—To define the repair pathways acting on the CC-1065 family of minor groove adduct in S. cerevisiae, we synthesized and characterized a close CC-1065 analogue, THIII151 (Fig. 1A), which alkylates DNA with a sequence selectivity indistinguishable from CC-1065 [36]
We compared the THIII151 sensitivity of a repair-proficient parent strain (DBY747) to an isogenic rad4 disruptant that is completely deficient in NER (rad4 cells are totally NER-defective in contrast to their mammalian counterparts, XPC cells [2]) (Fig. 1B)
Summary
Nucleotide excision repair (NER)1 is the principal DNA repair pathway acting on bulky DNA lesions, such as those formed by ultraviolet light and cisplatin, in both prokaryotes and eukaryotes [1]. Our results indicate that the RAD5 subpathway may interact with NER factors during the repair of certain DNA adducts. RAD6 is the founder gene of a complex epistasis group that controls multiple DNA damage tolerance and repair pathways
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call