Premium
Mouse MCM proteins: complex formation and transportation to the nucleus
Author(s) -
Kimura Hiroshi,
Ohtomo Takatsugu,
Yamaguchi Masato,
Ishii Atsushi,
Sugimoto Kazunori
Publication year - 1996
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1046/j.1365-2443.1996.840284.x
Subject(s) - biology , chromatin , nucleus , nuclear pore , interphase , nuclear protein , nuclear transport , dna binding protein , microbiology and biotechnology , cell nucleus , molecular mass , dna replication , dna , biochemistry , gene , transcription factor , enzyme
Background : The members of the MCM protein family, including MCM2, MCM3, Cdc21, CDC46, Mis5 and CDC47, are considered to be involved in the control of a single round of DNA replication during S phase in eukaryotes. They bind to chromatin during G1 and detach from it during S phase as if they license the chromatin to replicate. However, unlike the originally proposed ‘licensing factor’ and the budding yeast homologues, mammalian MCM2 and P1MCM3 proteins appeared to be localized in the nucleus during the interphase. Results : We purified mCdc21 and its associated proteins from mouse cell extract by anti‐mCdc21 immunoaffinity chromatography. Three proteins which co‐purified with mCdc21 were identified as mCDC47, mMis5 and mMCM2, all were MCM proteins. Glycerol gradient centrifugation analysis showed that all the mouse MCM proteins were detected at 450–600 kDa, an indication of the sum of their calculated molecular weights from their amino acid sequences. mCdc21 was displaced from replicated chromatin in a similar way to P1MCM3 and MCM2 during S phase. Among the six mouse MCM proteins, only mMCM2 and mP1MCM3 showed nuclear localization when overexpressed in COS cells. Conclusions : We conclude that in the mouse, six MCM proteins form a single protein complex of molecular weight 450–600 kDa, which may enter the nucleus by nuclear localization signals in the mMCM2 and mP1MCM3 subunits.