ABSTRACT
This chapter employs the term proliferating cell nuclear antigen (PCNA) to denote this protein, mainly on the ground of historical precedence, but also because the name “cyclin” is used for other proteins and reagents, and “DNA polymerase-d auxiliary protein” is a cumbersome term (no disrespect intended to those who work with these entities). The synthesis and possibly the accumulation of cyclin (PCNA) are regulated through the cell cycle and correlate temporally with DNA replication. PCNA (defined immunologically) can substitute for the replication factor, each sediments as a dimer, and they have the same N-terminal amino acid sequence (which closely resembles that previously published for rabbit thymus PCNA). A high rate of PCNA synthesis would be expected simply from the proliferative activity of such cells, but early studies suggested that there might be a more specific connection with transformation. An anti-peptide serum has been prepared by injecting rabbits with a synthetic 13-residue peptide conjugated to keyhole limpet hemocyanin.
