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Deletion of Mnt leads to disrupted cell cycle control and tumorigenesis
Author(s) -
Hurlin Peter J.,
Zhou ZiQiang,
Toyooka Kazuhito,
Ota Sara,
Walker William L.,
Hirotsune Shinji,
WynshawBoris Anthony
Publication year - 2003
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdg442
Subject(s) - carcinogenesis , cell cycle , downregulation and upregulation , retinoblastoma protein , biology , knockout mouse , repressor , cancer research , conditional gene knockout , cell growth , cyclin d1 , cyclin , tumor suppressor gene , kinase , cyclin dependent kinase , microbiology and biotechnology , suppressor , gene , genetics , gene expression , phenotype
Mnt is a Max‐interacting transcriptional repressor that has been hypothesized to function as a Myc antagonist. To investigate Mnt function we deleted the Mnt gene in mice. Since mice lacking Mnt were born severely runted and typically died within several days of birth, mouse embryo fibroblasts (MEFs) derived from these mice and conditional Mnt knockout mice were used in this study. In the absence of Mnt, MEFs prematurely entered the S phase of the cell cycle and proliferated more rapidly than Mnt +/+ MEFs. Defective cell cycle control in the absence of Mnt is linked to upregulation of Cdk4 and cyclin E and the Cdk4 gene appears to be a direct target of Mnt–Myc antagonism. Like MEFs that overexpress Myc, Mnt −/− MEFs were prone to apoptosis, efficiently escaped senescence and could be transformed with oncogenic Ras alone. Consistent with Mnt functioning as a tumor suppressor, conditional inactivation of Mnt in breast epithelium led to adenocarinomas. These results demonstrate a unique negative regulatory role for Mnt in governing key Myc functions associated with cell proliferation and tumorigenesis.