Submitted to: Molecular and Cellular Biology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/30/2005
Publication Date: 2/1/2006
Citation: Guzder, S.N., Sommers, C.H., Prakash, L., Prakash, S. 2006. Complex formation with damage recognition protein rad14 is essential for saccharomyces cerevisiae rad1-rad10 nuclease to perform its function in nucleotide excision repair in vivo. Molecular and Cellular Biology. 26(3): 1135-1141. Interpretive Summary: Damage to DNA and chromosomes caused by UV light and chemicals in yeast, rodents and humans is normally repaired by special proteins that remove the damage and repair the DNA. Humans who suffer from the genetic diseases Xeroderma pimentosum and Cockayne’s Syndrome are not able to repair DNA damaged by UV light and chemicals, and die before their teens from cancer. The proteins involved in the repair of DNA in humans and yeast are almost identical. Determining the function of DNA repair proteins in yeast can therefore help determine the function of the equivalent proteins in humans. In this work one of the functions of the Rad1-Rad10-Rad14 protein complex in removing damage from the chromosomes of yeast was determined. This will help identify the function of the equivalent protein complex (XPA-ERRC1-XPF) in human cells, and lead to a better understanding of human genetic diseases Xeroderma pimentosum and Cockayne’s Syndrome.
Technical Abstract: Nucleotide excision repair (NER) in eukaryotes requires the assembly of a large number of protein factors at the lesion site which then coordinate the dual incision of the damaged DNA strand. Howevr, the manner by which the different protein factors are assembled at the lesion site has remained unclear. Previously, we have shown that in the yeast Saccharomyces cerevisiae, NER proteins exist as components of different protein subassemblies: the Rad1-Rad10 nuclease, for example, forms a tight complex with the DNA recognition protein Rad14, and the complex Rad1-Rad10-Rad14 can be purified intact from yeast cells. As the Rad1-Rad10 nuclease shows no specificity for binding UV lesions in DNA, association with Rad14 could provide effective means for targeting of the Rad1-Rad10 nuclease to damage sites in vivo. To test the validity of this idea, here we identify two rad1 mutations that render yeast cells as UV sensitive as the rad1 deletion mutation, but which have no effect on the recombination function of Rad1. From our genetic and biochemical studies with these rad1 mutations, we conclude that the ability of Rad1-Rad10 nuclease to associate in a complex with Rad14 is paramount for the targeting of this nuclease to lesion sites in vivo. We discuss the implications of these observations by which the different NER proteins are assembled at the lesion site.