Sequential assembly of translesion DNA polymerases at UV-induced DNA damage sites.

ABSTRACT: In response to DNA damage such as from UV irradiation, mammalian Y-family translesion synthesis (TLS) polymerases Pol? and Rev1 colocalize with proliferating cell nuclear antigen at nuclear foci, presumably representing stalled replication sites. However, it is unclear whether the localization of one polymerase is dependent on another. Furthermore, there is no report on the in vivo characterization of the Rev3 catalytic subunit of the B-family TLS polymerase Pol?. Here we describe the detection of endogenous human Pol?, Rev1, and Rev3 by immunocytochemistry using existing or newly created antibodies, as well as various means of inhibiting their expression, which allows us to examine the dynamics of endogenous TLS polymerases in response to UV irradiation. It is found that Rev1 and Pol? are independently recruited to the nuclear foci, whereas the Rev3 nuclear focus formation requires Rev1 but not Pol?. In contrast, neither Rev1 nor Pol? recruitment requires Rev3. To further support these conclusions, we find that simultaneous suppression of Pol? and Rev3 results in an additive cellular sensitivity to UV irradiation. These observations suggest a cooperative and sequential assembly of TLS polymerases in response to DNA damage. They also support and extend the current polymerase switch model.

SUBMITTER: Andersen PL 

PROVIDER: S-EPMC3128538 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature