Prep1 directly regulates the intrinsic apoptotic pathway by controlling Bcl-XL levels

Nicola Micali, Carmelo Ferrai, Luis C. Fernandez-Diaz, Francesco Blasi, Massimo P. Crippa

Research output: Contribution to journalArticlepeer-review


The Prep1 homeodomain transcription factor is essential in embryonic development. Prep1 hypomorphic mutant mouse (Prep1 i/i) embryos (embryonic day 9.5) display an increased terminal deoxynucleotidyltransferase- mediated dUTP-biotin nick end labeling reaction compared to wild-type (WT) littermates. Prep1 i/i mouse embryo fibroblasts (MEFs) show an increased basal level of annexin V binding activity, reduction of the mitochondrial-membrane potential, and increased caspase 9 and 3 activation, indicating increased apoptosis. Prep1 i/i MEFs also respond faster than WT MEFs to genotoxic stress, indicating increased activation of the intrinsic apoptotic pathways. We did not observe an increase in p53 or an abnormal p53 response to apoptotic stimuli. However, hypomorphic MEFs have decreased endogenous levels of antiapoptotic Bcl-X L mRNA and protein, and Bcl-x overexpression rescues the defect of Prep1 i/i MEFs. Using transient transfections and chromatin immunoprecipitation, we identified the Bcl-x promoter as a novel target of Prep1. Thus, Prep1 directly controls mitochondrial homeostasis (and the apoptotic potential) by modulating Bcl-x gene expression.

Original languageEnglish
Pages (from-to)1143-1151
Number of pages9
JournalMolecular and Cellular Biology
Issue number5
Publication statusPublished - Mar 2009

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology


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