A DDB2 mutant protein unable to interact with PCNA promotes cell cycle progression of human transformed embryonic kidney cells

Recently, it has been suggested that DDB2 may play a role in DNA replication, based on its ability to promote cell proliferation. We have previously shown that DDB2 binds PCNA during NER, but also in the absence of DNA damage; however, whether and how this interaction influences cell proliferation is not known.

In this study, we have addressed this question by using HEK293 cell clones stably expressing DDB2 Wt protein, or a mutant form (DDB2 Mut ) unable to interact with PCNA. We report that overexpression of the DDB2 Mut protein provides a proliferative advantage over the wild type form, by influencing cell cycle progression. In particular, an increase in the number of S-phase cells, together with a reduction in p21 CDKN1A protein level, and a shorter cell cycle length, has been observed in the DDB2 Mut cells.