hCDC47, a human member of the MCM family. Dissociation of the nucleus-bound form during S phase.
hCDC47 is a putative human homologue of yeast CDC47 and a member of the MCM protein family, which has been implicated in the regulatory machinery causing DNA to replicate only once in the S phase. In the present study, we performed an initial characterization of hCDC47. We found that hCDC47 protein was present in the nucleus of cultured human cells in two different forms; one extractable by a non-ionic detergent and the other resistant to such extraction and tightly associated with the nucleus. The levels of the nucleus-bound form gradually diminished during S phase progression, although the total amount of nuclear hCDC47 protein remained relatively constant, suggesting that the nucleus-bound form becomes dissociated from the nuclear structure during DNA replication. This behavior of hCDC47 protein is very similar to that of other mammalian MCM proteins reported recently. We also found that expression of hCDC47 mRNA was repressed in quiescent cells but was induced at the late G1 to S phase by growth factor stimulation. Together, these findings indicate that hCDC47 protein together with other MCM proteins participates in the regulation of mammalian DNA replication.
Fujita
M
M
Laboratory of Viral Oncology, Research Institute, Aichi Cancer Center, Chikusa-ku, Nagoya 464, Japan.
Kiyono
T
T
Hayashi
Y
Y
Ishibashi
M
M
D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D003001:Cloning, Molecular; D004261:DNA Replication; D004268:DNA-Binding Proteins; D005434:Flow Cytometry; D005656:Fungal Proteins / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D064168:Minichromosome Maintenance Complex Component 7; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009687:Nuclear Proteins; D016196:S Phase; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D016324:Sequence Tagged Sites; D013347:Subcellular Fractions / Q000378:metabolism
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; C491088:MCM7 protein, S cerevisiae; C101624:MCM7 protein, human; D064168:Minichromosome Maintenance Complex Component 7