Abstract
DNA damage recognition during nucleotide excision repair (NER) involves the homologous heterodimers Rad4:Rad23 in budding yeast and XPC:hHR23B in human. We report here the characteristics of four Arabidopsis homologues of RAD23 gene, named AtRAD23-1 to-4. AtRAD23-1, -3 and -4 expressed two alternatively spliced transcripts, long ones (AtRAD23-1α, -3α and -4α) and short ones (AtRAD23-1β, -3β and -4β). The predicted amino acid sequences of these genes possessed four conserved domains of Rad23 family; the ubiquitin-like domain, ubiquitin-associated domain I, XPC-binding domain and ubiquitin-associated domainII. AtRad23-3 βand-4 βlacked the C-terminus ubiquitin-like domain and the C-terminus XPC-binding domain, respectively, suggesting that these alternatively spliced variants may modulate functional AtRad23 proteins. Phylogenetic analysis showed that plant RAD23 genes could be divided into two classes and that Arabidopsis RAD23 genes were recently duplicated. AtRAD23-1-4 transcripts were detected in various tissues, with the highest expression level in flower buds.
