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Institute for Research in Biomedicine
Istituto di Ricerca in Biomedicina

Via Vincenzo Vela 6 - CH-6500 Bellinzona
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New paper from Cejka's Lab

on Thursday, May 7, 2020

CtIP has emerged as one of the main factors that drives the processing of broken DNA into the homologous recombination pathway. CtIP achieves that by stimulating the activity of two nucleases (MRE11 and DNA2), which resect DNA end creating single-strand DNA overhangs required for the downstream steps in the recombination pathway. Cell lacking CtIP consequently exhibit abrogated DNA end resection and homologous recombination.

A recent study from the Cejka laboratory at IRB, affiliated with USI, shows that a CtIP variant lacking parts of its central domain is even more efficient than the wild type protein. This unexpected result identified that the central domain of CtIP functions as an inhibitor of DNA end resection, and CtIP can regulate the efficacy of DNA end resection both positively and negatively. The study was published in Nucleic Acids Research.

The internal region of CtIP inhibits single strand annealing. Schematic of Sae2 and CtIP protein variants used in this study. Key domains and phosphorylation sites (P) are indicated. Missing amino acid regions in CtIP internal deletion mutants are indicated by a black line.


The internal region of CtIP negatively regulates DNA end resection.

Howard, S. M., I. Ceppi, R. Anand, R. Geiger and P. Cejka

Nucleic Acids Res. 2020