Chromatin Bound PCNA is Complexed with Cell Cycle Protein Regulators as Determined by Chromatin Immunoprecipitation

Using the technique of Chromatin Immunoprecipitation, we have detected the formation of complexes between the homotrimer protein ring Proliferating Cell Nuclear Antigen, PCNA, and two fundamental regulators of the cell cycle, CdkA and Cyclin D4;2 along germination of maize seeds. This finding suggests the way PCNA participates in the control of the G1 phase, by allowing cyclin-kinase complexes to find and phosphorylate protein targets. Incidentally, PCNA may form a structure of a dimer of trimer when bound to the chromatin.