Abstract Cells are often under attack from various DNA-damaging agents. Accurate repair is required to protect cells the genome instability induced by DNA lesions. damage response (DDR) signaling involves sensitizing, transmitting, and repairing different types of within chromatin complexes. Chromatin a highly ordered complex packed with repeating units nucleosomes linker sequences. structure, ...

The archaeal/eukaryotic proliferating cell nuclear antigen (PCNA) toroidal clamp interacts with a host of DNA modifying enzymes, providing a stable anchorage and enhancing their respective processivities. Given the broad range of enzymes with which PCNA has been shown to interact, relatively little is known about the mode of assembly of functionally meaningful combinations of enzymes on the PCN...

DNA ligases are enzymes required for the repair, replication and recombination of DNA. DNA ligases catalyse the formation of phosphodiester bonds at single-strand breaks in double-stranded DNA. Despite their occurrence in all organisms, DNA ligases show a wide diversity of amino acid sequences, molecular sizes and properties. The enzymes fall into two groups based on their cofactor specificity,...

tion signal of the genome that plays important roles in heritable gene silencing, heterochromatin formation and certain transgenerational epigenetic inheritance. In contrast to the process of DNA methylation that is catalyzed by specific classes of methyltransferases, molecular players underlying active DNA demethylation have long been elusive. Emerging biochemical and functional evidence sugge...

Cellular responses to DNA damage involve distinct DNA repair pathways, such as mismatch repair (MMR) and base excision repair (BER). Using Caenorhabditis elegans as a model system, we present genetic and molecular evidence of a mechanistic link between processing of DNA damage and activation of autophagy. Here we show that the BER AP endonucleases APN-1 and EXO-3 function in the same pathway as...

DNA double-strand breaks (DSBs) can be repaired by homologous recombination (HR), which can involve Holliday junction (HJ) intermediates that are ultimately resolved by nucleolytic enzymes. An N-terminal fragment of human GEN1 has recently been shown to act as a Holliday junction resolvase, but little is known about the role of GEN-1 in vivo. Holliday junction resolution signifies the completio...

1. Introduction DNA repair can occur by a variety of mechanistically distinct pathways [for review, see (1)]. Recombinational DNA repair is one such pathway, and it requires the coordinated action of many different enzymes. In the best studied organism, Escherichia coli, more than 20 different proteins are involved [for review, see (2)]. The recombinational repair of a double-stranded DNA (dsDN...

DNA primases are essential for the initiation of DNA replication and progression of the replication fork. Recent phylogenetic analyses coupled with biochemical and structural studies have revealed that the arrangement of catalytic residues within the archaeal and eukaryotic primase has significant similarity to those of the Pol X family of DNA-repair polymerases. Furthermore, two additional gro...

Bacteria (Escherichia coli) can recover from the lethal action of N-hydroxyurethan when they are incubated in drug-free liquid medium. This recovery, which is dependent upon energy metabolism, does not occur on solid medium. Recovery is accompanied by repair of the cellular deoxyribonucleic acid (DNA). A bacterial mutant deficient in DNA polymerase was extremely sensitive to the lethal action o...