XPA Binding Protein 2 (XAB2)

Using yeast 2-hybrid analysis of a HeLa cDNA library with XPA as bait, followed by RACE PCR, Nakatsu et al. (2000) cloned XAB2. The 855-amino acid protein has 3 acidic regions, 15 class I tetratricopeptide repeats, and a conserved C-terminal region.By in vitro pull-down assay, Nakatsu et al. (2000) confirmed the specific interaction of XPA and XAB2 in yeast. Coimmunoprecipitation assays showed that XAB2 also interacts with CSA (ERCC8), CSB (ERCC6) and RNA polymerase II both in vitro and in vivo. Microinjection of XAB2 antibodies in primary fibroblasts and fibroblasts from XPC patients inhibited mRNA synthesis and transcription-coupled repair (TCR), but did not affect global genome repair (GGR), suggesting that XAB2 functions in normal transcription and in TCR.