Analysis of protein interaction partners of TDIF

Reactive oxygen species (ROS) generated as by-products of metabolism can induce stochastic damage to cellular components including DNA. A localised oxidative damage may arise during transcriptional activation at promoters of protein coding genes. ROS are generated during oxidative demethylation of histones and 5-methyl cytosine in promoter CpG clusters. ROS induced oxidation of DNA bases, mainly 7,8-dihydro-8-oxoguanine (8-oxoG) is normally resolved through a well characterised repair pathway where the oxidised base is first removed by components of base excision repair (BER) pathway, and the resulting breaks in the DNA backbone are subsequently repaired by the single-strand repair (SSBR) machinery that includes TDP1 and XRCC1. In this project we have identified the role of a putative mitotic assembly protein, TDIF in ROS induced single strand break repair. Using semi-quantitative LC-MS/MS and biochemical assays we show that the long isoform of TDIF specifically interacts with SSBR machinery after oxidative damage.