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. Author manuscript; available in PMC: 2008 Oct 30.
Published in final edited form as: Prog Nucleic Acid Res Mol Biol. 2006;81:179–229. doi: 10.1016/S0079-6603(06)81005-6

Table 4.

Genetic alterations conferring hypersensitivity to Top1 poisoning in fission yeast:

Yeast Saccharomyces Pombe
 Humans
Gene Effect Refs. Function Gene Effect Refs.
Rhp54 HS [129] Homologous recombination (HR) RAD52 ?
Rhp55 LS [129] Homologous recombination (HR) XRCC2 HS [219, 230, 234]
Rhp22A LS [129] Homologous recombination (HR) XRCC3 HS [219]
Rhp51 S [129] RecA homolog; Rad52 epistasis G. RAD51C HS [223]
rad22 HS [248] Rec A homolog; functions with Mus81
Rad50 HS [129] MRX/N complex; scaffold RAD50 ?
Mus81 S [129] 3′-flap endonuclease with Eme1; meiotic recombination MUS81 NS [137]
Eme1 S [129] Partner for mus81 nuclease MUS81 ?
RusA RSa [129] HJ resolvase
Pnk1 Sb [112] Polynucleotide kinase phosphatase PNKP HS [115]
Rqh1 MS [98] Top3-associated helicase WRN HS [227–229]
BLM HS [82]
Crb2 S [249] Adaptor for checkpoint kinases and checkpoint proteins 53BP1 ?
BRCA1 HS [216]
Chk1 S [155, 249, 250] Checkpoint effector kinase CHK1 S [162, 165]
Swi1 HS [251] Mating-type switching TIMELESS

Abbreviations for effect: HS, S, MS, and CS correspond to hypersensitivity, sensitivity, moderate sensitivity, and conditional sensitivity to camptothecin, respectively. NS: no hypersensitivity.

a

rusA suppresses hypersensitivity of Mus81/Eme1− but does not reverse sensitivity of rqh1−; rusA also suppresses the lethality of double mutants for Mus81/Eme1 + rqh1 [129]. RusA expressed in budding yeast partially suppresses hypersensitivity to CPT in Mms4-deficient cells [126].

b

Pnk1- cells are hypersensitive to CPT in the absence of additional defects, indicating difference from budding (see [a]) and importance of this pathway in fission yeast, which like mammals possesses a gene that has both 3′-phosphatase and 5′-kinase activity [112].