Gene for proliferating-cell nuclear antigen (DNA polymerase delta auxiliary protein) is present in both mammalian and higher plant genomes.
Proliferating-cell nuclear antigen (PCNA; also called cyclin) was originally described in proliferating mammalian cells as a nuclear protein with an apparent Mr of 33,000-36,000 and recently was found to be a DNA polymerase delta auxiliary protein. To elucidate whether PCNA/cyclin is a universal protein necessary for proliferation of eukaryotes, a search was conducted for PCNA/cyclin homologues in higher plants. In Southern blot-hybridization analysis, a rat PCNA/cyclin cDNA probe hybridized with homologous sequences in genomic DNAs from rice, soybean, and tobacco. A PCNA/cyclin-related molecular clone (pCJ-1) was isolated from rice DNA and was partially sequenced. The pCJ-1 probe hybridized with a 1.2-kilobase transcript in RNA from rice root tips and shoots. Immunoblot analysis of the soluble extract of soybean root tips with monospecific anti-PCNA/cyclin identified an immunoreactive protein with an apparent Mr of 34,000. Immunohistochemical analysis revealed the presence of an immunoreactive PCNA/cyclin protein in the nuclei of cells in the meristem of soybean root tips. The highly homologous nature of the gene for PCNA/cyclin throughout the animal and plant kingdoms suggests that the product of the gene plays an essential role in DNA replication in eukaryotes.
Suzuka
I
I
Department of Molecular Biology, National Institute of Agrobiological Resources, Tsukuba Science City, Japan.
Daidoji
H
H
Matsuoka
M
M
Kadowaki
K
K
Takasaki
Y
Y
Nakane
P K
PK
Moriuchi
T
T
D000595:Amino Acid Sequence; D000818:Animals; D001324:Autoantigens; D001483:Base Sequence; D002467:Cell Nucleus / Q000032:analysis; D004247:DNA / Q000235:genetics*; D015342:DNA Probes; D006801:Humans; D007150:Immunohistochemistry; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009687:Nuclear Proteins / Q000235:genetics*; D009693:Nucleic Acid Hybridization; D012275:Oryza; D010944:Plants / Q000235:genetics*; D010947:Plants, Toxic; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D012689:Sequence Homology, Nucleic Acid; D013025:Glycine max; D014026:Nicotiana; D014158:Transcription, Genetic
D001324:Autoantigens; D015342:DNA Probes; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D004247:DNA