Meis1 induces and Prep1 suppresses tumors by exploiting low affinity AP1 binding sites.
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ABSTRACT: We have defined the tumor and tumor suppressor signature for Meis1 and Prep1 (pKnox1), respectively, using ChIP-seq and RNA-seq in a cell system in which tumor suppressor Prep1 and oncogene Meis1 compete for tumorigenesis [GSE54221; GSE58802]. In this paper we report that the number of Meis1 or Prep1 DNA binding sites increases linearly with the level of expression of the two transcription factors. Overexpression of Meis1 induces tumors. At the molecular level it modifies the DNA target specificity by increasing the number of low-affinity binding sites, which results in a different choice of consensus sequences with predominance of sites normally bound by the AP1 transcription factor family. Upon concomitant overexpression of Prep1 and Meis1 tumorigenesis is inhibited. Prep1 dominates over Meis1 not only because it partially decreases Meis1 protein level but also because it prevents the binding to a substantial fraction of the low affinity binding sites. Overall, overexpression of Prep1 reverses the nature of the bound and regulated genes from stimulatory to inhibitory of signal transduction and transcription, which suppresses tumorigenesis. By identifying the Meis1 tumor signature, specific relevant signaling pathways are identified. In line with these results, tumorigenic Meis1-overexpressing cells are uniquely hypersensitive to inhibitors of the MAPK/Akt pathways.
ORGANISM(S): Mus musculus
PROVIDER: GSE58818 | GEO | 2016/06/25
SECONDARY ACCESSION(S): PRJNA253583
REPOSITORIES: GEO
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