1989 Volume 22 Issue 1 Pages 105-116
PCNA/cyclin was originally described in proliferating mammalian cells as a nuclear protein with an apparent molecular weight of 33, 000-36, 000, and recently found to be a DNA polymerase-delta auxiliary protein. When the cDNA for PCNA/cyclin was cloned and analyzed, it was found that the protein consisted of 261 amino acids with a calculated molecular weight of 28, 700 and the amino acid sequence was well conserved during evolution both in animal and plant kingdoms. The highly homologous nature of PCNA/cyclin suggests that the protein plays an essential role in DNA replication in eukaryotes.
