Final answer:
Proliferating cell nuclear antigen (PCNA) is a key protein in DNA replication and repair related to the cell cycle in eukaryotes. It works with proto-oncogenes and tumor suppressor genes, like p53, to maintain genomic stability and prevent cancer.
Step-by-step explanation:
Proliferating cell nuclear antigen (PCNA) is a protein that plays a pivotal role in DNA replication and repair, commonly associated with the cell cycle in eukaryotic organisms.
PCNA acts as a sliding DNA clamp and is a key component in the machinery that copies DNA before cell division. This protein ensures that the genetic material is accurately replicated and any errors are corrected. It is intricately involved in the regulation of the cell cycle and, when functioning correctly, helps maintain genomic stability.
Proto-oncogenes are normal genes that regulate cell division and promote the growth and reproduction of cells, but they can become a primary factor in the development of cancer if mutated into oncogenes.
Tumor suppressor genes, like the gene that produces the p53 protein, work to counteract the effects of proto-oncogenes by detecting DNA anomalies and enabling repair, or triggering apoptosis if repair is not possible. Therefore, a mutated p53 gene can cause a cell to ignore DNA damage and continue dividing, potentially leading to cancer.