Table I.

Example of Available DT40 Mutant Cell Lines

BER	NER	NHEJ	HR
- POL β	- XPA	- KU70	- RAD52
- FEN1	- XPG	- LIG IV	- RAD54
- PARP1		- DNAPKcs	- RAD51c
DNA damage sensors	MMR	TLS	- RAD51d
	- MSH2	- POL K	- XRCC2
- RAD9	- MSH3	- POL Q	- XRCC3
- RAD17	- MSH6	- POL Q	- BRCA1
Helicase		- REV1	- BRCA2
- BLM		- REV3	- FANCD2
- WRN		- RAD18

DNA damage repair/tolerance pathways represented:

BER - base excision repair; NER – nucleotide excision repair; NHEJ – non - homologous end- joining; HR – homologous recombination; MMR – mis-match repair; TLS – trans-lesion synthesis