Human and Xenopus cDNAs encoding budding yeast Cdc7-related kinases: in vitro phosphorylation of MCM subunits by a putative human homologue of Cdc7.
Saccharomyces cerevisiae Cdc7 kinase is essential for initiation of DNA replication, and Hsk1, a related kinase of Schizosaccharomyces pombe, is also required for DNA replication of fission yeast cells. We report here cDNAs encoding Cdc7-related kinases from human and Xenopus (huCdc7 and xeCdc7, respectively). The cloned cDNA for huCdc7 contains an open reading frame consisting of 574 amino acids with a predicted molecular weight of 63,847 that possesses overall amino acid identity of 32% (54% including similar residues) to Cdc7 and Hsk1. huCDC7 is transcribed in the various tissues examined, but most abundantly in testis. Three transcripts of 4.4, 3.5 and 2.4 kb in length are detected. The 3.5 kb transcript is the most predominant and is expressed in all the tissues examined. A cDNA containing a 91 nucleotide insertion at the N-terminal region of huCDC7 is also detected, suggesting the presence of multiple splicing variants. The huCdc7 protein is expressed at a constant level during the mitotic cell cycle and is localized primarily in nuclei in interphase and distributed diffusibly in cytoplasm in the mitotic phase. The wild-type huCdc7 protein expressed in COS7 cells phosphorylates MCM2 and MCM3 proteins in vitro, suggesting that huCdc7 may regulate processes of DNA replication by modulating MCM functions.
Sato
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N
Department of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, Minato-ku, Japan.
Arai
K
K
Masai
H
H
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000201:enzymology; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000201:enzymology; D004268:DNA-Binding Proteins / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D008856:Microscopy, Fluorescence; D064126:Minichromosome Maintenance Complex Component 3; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D051738:Origin Recognition Complex; D010766:Phosphorylation; D010802:Phylogeny; D011494:Protein Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000201:enzymology; D029702:Schizosaccharomyces pombe Proteins; D014981:Xenopus; D029867:Xenopus Proteins
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C066470:MCM3 protein, human; D009687:Nuclear Proteins; D051738:Origin Recognition Complex; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D029867:Xenopus Proteins; D011494:Protein Kinases; C489404:CDC7 protein, S cerevisiae; C489405:CDC7 protein, Xenopus; C068619:CDC7 protein, human; C489406:cdc7 protein, S pombe; D017346:Protein Serine-Threonine Kinases; D064126:Minichromosome Maintenance Complex Component 3