. Author manuscript; available in PMC: 2015 Jul 1.

Published in final edited form as: DNA Repair (Amst). 2014 May 22;19:114–129. doi: 10.1016/j.dnarep.2014.03.020

Table 1.

Exogenous and endogenous factors producing Top1 cleavage complexes and relevant for TDP1.

Endogenous DNA lesions	Notes	Refs. [163,164]
Single base mismatches	Polymerase and mismatch defects	[163,165]
Mismatched loops	Mismatch deficiencies	[165]
Abasic sites	Abasic sites; BER^*	[165]
8-Oxoguanosine	Free radicals	[166]
5-Hydroxycytosine	Free radicals	[166]
Single-strand breaks	Free radicals; base excision repair	[16,167]
Cytosine methylation	Physiological	[168]
Triple helix formation	Physiological	[169]
Apoptotic chromatin fragmentation	Ubiquitous during apoptosis	[164,170–172]
Exogenous DNA lesions		[163]

UV lesions	Dimers and 6,4-photoproducts	[173,174]
IR-induced DNA breaks	Both single- and double-strand breaks	[16]
O⁶- or N⁷- or O³-methylguanine	Alkylating drugs (MNNG, MMS, TMZ)^*	[45,53,175]
O⁶-dA-benzo[a]pyrene adducts	Intercalated carcinogenic adducts	[176]
N²-dG-benzo[a]pyrene adducts	Minor groove carcinogenic adducts	[177,178]
N²-dG-benzo[c]phenanthrene adducts	Intercalated carcinogenic adducts	[178]
N⁶-ethenoadenine	Carcinogenic vinyl adduct	[179]
N²-dG-ethyl adducts	Produced by acetaldehyde (alcohol)	[180]
N²-dG-crotonaldehyde adducts	Exogenous carcinogens and endogenous	[181]

BER: base excision repair; MNNG: methylnitronitrosoguanine; MMS: methylmethanesulfonate; TMZ: temozolomide.