Proliferating Cell Nuclear Antigen (PCNA) is a protein known for its function in DNA replication in all eukaryotic
cells. PCNA also has a role in DNA repair when exterior factors, like mutagenic UV-B radiation of sunlight, free
radicals, ionizing radiations, chemical mutagens, etc., result in damage to DNA either genetoxically or cytotoxically.
PCNA is usually of a toroidal shape and is made-up of either homo- or hetero-trimers. PCNA in Arabidopsis thaliana has
two subunits; PCNA1 and PCNA2 that forms a homotrimeric structure. We found that the two subunits (PCNA1 and
PCNA2) have a 97% similarity in their structures. Many studies have been conducted on PCNA from humans or yeast,
but there is very little research done on plant PCNA. This study aims to close that gap, by conducting a study on PCNA
subunits in Arabidopsis thaliana by predicting its 3D structure, domain analysis, subcellular localization, docking site
prediction and PCNA interactome. Interactome analysis of PCNA revealed that it interacts with many proteins in DNA
repair, such as Rad5, RAD9, RFC3, RFC5, RFC1, which are all a part of pathways involved in DNA repair. Interestingly
we found that PCNA interacts with AtBRD1which is controlling shoot differentiation and meristem organization.