title: A functional genome-wide RNAi screen identifies TAF1 as a regulator for apoptosis in response to genotoxic stress.
abstract: Evasion from apoptotic cell death is a characteristic of cancer; genes that modulate this process may be optimal for therapeutic attack. Identifying key regulators of apoptosis is thus a central goal in cancer therapy. Here, we describe a loss-of-function screen that uses RNA interference libraries to identify genes required for induction of apoptosis. We used a short-hairpin RNA expressing vector with high gene-expression silencing activity that contained fetal brain cDNAs. Survived cells from genotoxic stress were isolated to determine knock-down of molecules that are crucial for induction of apoptosis. We identified TBP-associated factor 1 (TAF1), a gene previously implicated as an essential component of transcription machinery. Depletion of TAF1 was associated with substantial attenuation of apoptosis induced by oxidative as well as genotoxic stress. Microarray analysis further demonstrated that a number of genes were transcriptionally declined in cells silenced for TAF1. Surprisingly, knocking down TAF1 exhibited a marked decrease in p27(Kip1) expression, allowing cells resistant from oxidative stress-induced apoptosis. These results suggest that TAF1 regulates apoptosis by controlling p27(Kip1) expression. Our system provides a novel approach to identifying candidate genes that modulate apoptosis.
authors.affiliation: Department of Molecular Genetics, Medical Research Institute, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8510, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Kimura
authors.forename: Su Tien
authors.initials: ST
authors.lastname: Nguyen
authors.forename: Hanshao
authors.initials: H
authors.lastname: Liu
authors.forename: Naoe
authors.initials: N
authors.lastname: Taira
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Miki
authors.forename: Kiyotsugu
authors.initials: K
authors.lastname: Yoshida
mesh_terms: D017209:Apoptosis / Q000235:genetics*; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000235:genetics / Q000378:metabolism; D005047:Etoposide / Q000633:toxicity; D005786:Gene Expression Regulation; D015894:Genome, Human; D051548:Histone Acetyltransferases; D006801:Humans; D018384:Oxidative Stress; D034622:RNA Interference; D035381:TATA-Binding Protein Associated Factors / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000502:physiology; D035362:Transcription Factor TFIID / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000502:physiology
chemical_list: D051017:Apoptosis Regulatory Proteins; D018797:Cell Cycle Proteins; D035381:TATA-Binding Protein Associated Factors; D035362:Transcription Factor TFIID; D050760:Cyclin-Dependent Kinase Inhibitor p27; D005047:Etoposide; D051548:Histone Acetyltransferases; C069001:TATA-binding protein associated factor 250 kDa