Biology!

Does anybody know where PCNA is located, I can't fucking find shit (thanx, Google). Also, does anybody know how the killing effects of UV light work vs. the mutagenic effects? I'm assuming, the former causes disruptions in metabolism whereas the other one acts by causing pyrimidine dimers in DNA.

Well, that's what I'd assume. That there is so much damage to the DNA that either apoptosis occurs or no amount of translesion synthesis can replicate past the amount of present dimers.