Host: The Japan Radiation Research Society
Co-host: City of Kitakyushu, University of Occupational and Environmental Health, Japan
Post-replication repair pathway (PRR) protects cells from a wild variety of DNA damage. Translesion DNA synthesis (TLS) in one of sub-pathway of PRR, in which a number of non-essential DNA polymerases is recruited to the 3'-ends and extends it beyond the lesions, rescues stalled replication. In eukaryotes, RAD6-RAD18 dependent mono-ubiquitination at the lysine 164 residue of proliferating cell nuclear antigen (PCNA) is deemed to play a key role in regulation of TLS. Indeed, RAD18 deficient human cells exhibit sensitivity to ionizing radiation, indicating a functional role of PRR for protection against ionizing radiation. In this work, we analyzed molecular mechanism for PCNA mono-ubiquitination using reconstituted system in vitro. The results demonstrated that PCNA molecules loaded on DNA by RFC are target of RAD6-RAD18 for ubiquitination.
