Ribonucleotide incorporation by human DNA polymerase η impacts translesion synthesis and RNase H2 activity

• Published in: Nucleic acids research 2017-03, Vol.45 (5), p.2600-2614
• Main Authors: Mentegari, Elisa, Crespan, Emmanuele, Bavagnoli, Laura, Kissova, Miroslava, Bertoletti, Federica, Sabbioneda, Simone, Imhof, Ralph, Sturla, Shana J, Nilforoushan, Arman, Hübscher, Ulrich, van Loon, Barbara, Maga, Giovanni
• Format: Article
• Language: English
• Subjects: Cell Line; Cytidine Monophosphate - metabolism; DNA - biosynthesis; DNA Damage; DNA Repair; DNA-Directed DNA Polymerase - metabolism; Genome Integrity, Repair and; Guanine - analogs & derivatives; Guanine - metabolism; Humans; Ribonuclease H - metabolism; Ribonucleotides - metabolism; RNA - biosynthesis; Xeroderma Pigmentosum - genetics
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/gkw1275

Ribonucleotides (rNs) incorporated in the genome by DNA polymerases (Pols) are removed by RNase H2. Cytidine and guanosine preferentially accumulate over the other rNs. Here we show that human Pol η can incorporate cytidine monophosphate (rCMP) opposite guanine, 8-oxo-7,8-dihydroguanine, 8-methyl-2΄-deoxyguanosine and a cisplatin intrastrand guanine crosslink (cis-PtGG), while it cannot bypass a 3-methylcytidine or an abasic site with rNs as substrates. Pol η is also capable of synthesizing polyribonucleotide chains, and its activity is enhanced by its auxiliary factor DNA Pol δ interacting protein 2 (PolDIP2). Human RNase H2 removes cytidine and guanosine less efficiently than the other rNs and incorporation of rCMP opposite DNA lesions further reduces the efficiency of RNase H2. Experiments with XP-V cell extracts indicate Pol η as the major basis of rCMP incorporation opposite cis-PtGG. These results suggest that translesion synthesis by Pol η can contribute to the accumulation of rCMP in the genome, particularly opposite modified guanines.