Identification and functional characterization of a new member of the human Mcm protein family: hMcm8.
The six minichromosome maintenance proteins (Mcm2-7) are required for both the initiation and elongation of chromosomal DNA, ensuring that DNA replication takes place once, and only once, during the S phase. Here we report on the cloning of a new human Mcm gene (hMcm8) and on characterisation of its protein product. The hMcm8 gene contains the central Mcm domain conserved in the Mcm2-7 gene family, and is expressed in a range of cell lines and human tissues. hMcm8 mRNA accumulates during G(1)/S phase, while hMcm8 protein is detectable throughout the cell cycle. Immunoprecipitation-based studies did not reveal any participation of hMcm8 in the Mcm3/5 and Mcm2/4/6/7 subcomplexes. hMcm8 localises to the nucleus, although it is devoid of a nuclear localisation signal, suggesting that it binds to a nuclear protein. In the nucleus, the hMcm8 structure-bound fraction is detectable in S, but not in G(2)/M, phase, as for hMcm3. However, unlike hMcm3, the hMcm8 structure-bound fraction is not detectable in G(1) phase. Overall, our data identify a new Mcm protein, which does not form part of the Mcm2-7 complex and which is only structure-bound during S phase, thus suggesting its specific role in DNA replication.
Gozuacik
Devrim
D
INSERM Unit 370/Pasteur Institute, Faculté de Médecine Necker-Enfants Malades, 156 rue de Vaugirard, 75730, Paris, France.
Chami
Mounia
M
Lagorce
David
D
Faivre
Jamila
J
Murakami
Yoshiki
Y
Poch
Olivier
O
Biermann
Esther
E
Knippers
Rolf
R
Bréchot
Christian
C
Paterlini-Bréchot
Patrizia
P
D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D002843:Chromatin / Q000378:metabolism; D003001:Cloning, Molecular; D017124:Conserved Sequence / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D016193:G1 Phase; D015870:Gene Expression; D006367:HeLa Cells; D006801:Humans; D064110:Minichromosome Maintenance Proteins; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016196:S Phase; D017422:Sequence Analysis, DNA; D014407:Tumor Cells, Cultured
D018797:Cell Cycle Proteins; D002843:Chromatin; D018076:DNA, Complementary; D009687:Nuclear Proteins; D012333:RNA, Messenger; C471623:MCM8 protein, human; D064110:Minichromosome Maintenance Proteins