Disease relevance of RAD4

• 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 [1].
• Cloning the Drosophila homolog of the xeroderma pigmentosum complementation group C gene reveals homology between the predicted human and Drosophila polypeptides and that encoded by the yeast RAD4 gene [2].
• We established the locations and characteristics of a number of spontaneously generated plasmid-borne RAD4 mutations that alleviate the toxicity of the wild-type gene in E. coli and of several mutagen-induced chromosomal mutations that inactivate the excision repair function of RAD4 [3].

High impact information on RAD4

• The carboxy terminus of Rad23 binds to the Rad4 DNA repair protein and creates a link between the DNA repair and proteasome pathways [4].
• The XP-C complementing clone XPCC encodes a highly hydrophilic protein which is composed of a predicted 823 amino acids and shares limited homology with the product of the yeast DNA repair gene RAD4 [5].
• The NEF4 complex regulates Rad4 levels and utilizes Snf2/Swi2-related ATPase activity for nucleotide excision repair [6].
• Yeast RAD4, its human ortholog Xp-C and their orthologs in other eukaryotes are DNA repair proteins which participate in nucleotide excision repair through a ubiquitin-dependent process [7].
• RAD4, which on the basis of sequence homology has been proposed to be the yeast XPC counterpart, seems to be involved in repair of both inactive and active yeast DNA, challenging the hypothesis that RAD4 and XPC are functional homologs [8].

Biological context of RAD4

• 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) [1].
• We have mapped the physical location of the RAD4 gene by insertional mutagenesis and by transcript mapping [1].
• 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 [1].
• The RAD4 gene of yeast required for the incision step of DNA excision repair and the REV2 (= RAD5) gene involved in mutagenic DNA repair could not be isolated from genomic libraries propagated in E. coli regardless of copy number of the shuttle vector in yeast [9].
• The Rad4-Rad23 complex is essential for both NER subpathways, Transcription Coupled Repair (TCR) and Global Genome Repair (GGR) [10].

Associations of RAD4 with chemical compounds

• However, the interaction of Rad23 with Rad4 is not only to control degradation of Rad4, but also to assist in assembling the NER incision complex at UV-induced cyclobutane pyrimidine dimers [11].
• Liquid-holding recovery (LHR) in excision-defective rad4 mutant of Saccharomyces cerevisiae inactivated by ultraviolet (UV) and diepoxybutane (DEB) [12].
• Purified Rad23 protein was unable to bind to DNA, but stimulated the binding activity of purified Rad4 protein to N-acetyl-2-aminofluorene-damaged DNA [13].

Regulatory relationships of RAD4

• As Rad23 also controls Rad4 levels, these results suggest a complex system for globally regulating repair activity in vivo by controlling turnover of Rad4 [6].
• The u.v.-sensitive rad4 mutant of yeast was found to decrease u.v.-induced reversion in the cdc8 and lys2 loci [14].

Other interactions of RAD4

• 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 [1].
• The RAD4 and RAD14 genes have a particular role in repair following exposure to those ethylating agents that preferentially alkylate oxygen, but not to those that preferentially ethylate nitrogen [15].
• A fragment of the yeast DNA repair protein Rad4 confers toxicity to E. coli and is required for its interaction with Rad7 protein [16].
• Such suppression has previously been observed with mutant alleles of RAD1 and RAD4 [17].
• The homology of YDR314C to Rad4, together with the similar relation of both proteins to Rad33 prompted us to propose RAD34 as name for the YDR314C gene [10].

Analytical, diagnostic and therapeutic context of RAD4

• RAD4 gene of Saccharomyces cerevisiae: molecular cloning and partial characterization of a gene that is inactivated in Escherichia coli [1].
• The RAD4 gene, which is toxic to Escherichia coli, was also identified among the primary transformants of a ligation library at a frequency of 0.18% [18].
• The size of Rad4 protein overexpressed in Escherichia coli was found to be 89 kDa by SDS-PAGE [19].

References