title: Large scale RNAi screen reveals that the inhibitor of DNA binding 2 (ID2) protein is repressed by p53 family member p63 and functions in human keratinocyte differentiation.
abstract: The inhibitor of DNA binding 2, dominant negative helix-loop-helix protein, ID2, acts as an oncogene and elevated levels of ID2 have been reported in several malignancies. Whereas some inducers of the ID2 gene have been characterized, little is known regarding the proteins capable to repress its expression. We developed siRNA microarrays to perform a large scale loss-of-function screen in human adult keratinocytes engineered to express GFP under the control of the upstream region of ID2 gene. We screened the effect of siRNA-dependent inhibition of 220 cancer-associated genes on the expression of the ID2::GFP reporter construct. Three genes NBN, RAD21, and p63 lead to a repression of ID2 promoter activity. Strikingly NBN and RAD21 are playing on major role in cell cycle progression and mitosis arrest. These results underline the pregnant need to silence ID2 expression at transcript level to promote cell cycle exit. Central to this inhibitory mechanism we find p63, a key transcription factor in epithelial development and differentiation, which binds specific cis-acting sequence within the ID2 gene promoter both in vitro and in vivo. P63 would not suppress ID2 expression, but would rather prevent excessive expression of that protein to enable the onset of keratinocyte differentiation.
authors.affiliation: CEA, IRTSV, Laboratoire Biopuces, 17 rue des Martyrs, 38054 Grenoble cedex 9, France.
authors.forename: Ning
authors.initials: N
authors.lastname: Wu
authors.forename: David
authors.initials: D
authors.lastname: Castel
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Debily
authors.forename: Maria Alessandra
authors.initials: MA
authors.lastname: Vigano
authors.forename: Olivier
authors.initials: O
authors.lastname: Alibert
authors.forename: Roberto
authors.initials: R
authors.lastname: Mantovani
authors.forename: Kristina
authors.initials: K
authors.lastname: Iljin
authors.forename: Paul-Henri
authors.initials: PH
authors.lastname: Romeo
authors.forename: Xavier
authors.initials: X
authors.lastname: Gidrol
mesh_terms: D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D004268:DNA-Binding Proteins; D005786:Gene Expression Regulation / Q000502:physiology*; D057809:HEK293 Cells; D006801:Humans; D051797:Inhibitor of Differentiation Protein 2 / Q000096:biosynthesis* / Q000235:genetics; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism*; D008938:Mitosis / Q000502:physiology; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000502:physiology; D034741:RNA, Small Interfering / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C497450:ID2 protein, human; D051797:Inhibitor of Differentiation Protein 2; C112156:NBN protein, human; D009687:Nuclear Proteins; D010750:Phosphoproteins; C429022:RAD21 protein, human; D034741:RNA, Small Interfering; C495901:TP53 protein, human; C115051:TP63 protein, human; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins