The structure and connectivity of protein-protein interaction (PPI) networks are maintained throughout evolution by coordinated changes (coevolution) of network proteins. Despite extensive research, relatively little is known regarding the molecular basis and functional implications of the coevolution of PPI networks. Here, we used proliferating cell nuclear antigen, a hub protein that mediates...

The error-free repair of double-strand DNA breaks by homologous recombination (HR) ensures genomic stability using undamaged homologous sequence to copy genetic information. While some of the aspects of the initial steps of HR are understood, the molecular mechanisms underlying events downstream of the D-loop formation remain unclear. Therefore, we have reconstituted D-loop-based in vitro recom...

Immunolocalization of cyclin/PCNA (proliferating cell nuclear antigen) was performed with monoclonal antibody using immunogold methods on ultrathin cryosections of fertilized mouse eggs. Immunolabeling in pronuclei was checked 20, 22, 24 and 26 h after HCG injection. A relation between onset of pronuclei migration (early S-phase) and appearance of colloidal particle clusters was found. Afterwar...

DNA polymerase ζ (Pol ζ) plays a key role in DNA translesion synthesis (TLS) and mutagenesis in eukaryotes. Previously, a two-subunit Rev3-Rev7 complex had been identified as the minimal assembly required for catalytic activity in vitro. Herein, we show that Saccharomyces cerevisiae Pol ζ binds to the Pol31 and Pol32 subunits of Pol δ, forming a four-subunit Pol ζ(4) complex (Rev3-Rev7-Pol31-Po...

The robustness of complex biological processes in the face of environmental and genetic perturbations is a key biological trait. However, while robustness has been extensively studied, little is known regarding the fragility of biological processes. Here, we have examined the susceptibility of DNA replication and repair processes mediated by the proliferating cell nuclear antigen (PCNA). Using ...

Proliferating cell nuclear antigen (PCNA) is a ring-shaped protein that encircles duplex DNA and plays an essential role in many DNA metabolic processes in archaea and eukarya. The eukaryotic and euryarchaea genomes contain a single gene encoding for PCNA. Interestingly, the genome of the euryarchaeon Thermococcus kodakaraensis contains two PCNA-encoding genes (TK0535 and TK0582), making it uni...

B cells use translesion DNA synthesis (TLS) to introduce somatic mutations around genetic lesions caused by activation-induced cytidine deaminase. Monoubiquitination at lysine(164) of proliferating cell nuclear antigen (PCNA(K164)) stimulates TLS. To determine the role of PCNA(K164) modifications in somatic hypermutation, PCNA(K164R) knock-in mice were generated. PCNA(K164R/K164R) mutants are b...

The gene encoding the proliferating cell nuclear antigen (PCNA), a sliding clamp of DNA polymerases, was cloned from an euryarchaeote, Thermococcus kodakaraensis KOD1. The PCNA homologue, designated Tk-PCNA, contained 249 amino acid residues with a calculated molecular mass of 28,200 Da and was 84.3% identical to that from Pyrococcus furiosus. Tk-PCNA was overexpressed in Escherichia coli and p...