A genome-wide RNA interference screen reveals that variant histones are necessary for replication-dependent histone pre-mRNA processing.
Wagner EJ, Burch BD, Godfrey AC, Salzler HR, Duronio RJ, Marzluff WF.
Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
Metazoan replication-dependent histone mRNAs are not polyadenylated and instead end in a conserved stem loop that is the cis element responsible for coordinate posttranscriptional regulation of these mRNAs. Using biochemical approaches, only a limited number of factors required for cleavage of histone pre-mRNA have been identified. We therefore performed a genome-wide RNA interference screen in Drosophila cells using a GFP reporter that is expressed only when histone pre-mRNA processing is disrupted. Four of the 24 genes identified encode proteins also necessary for cleavage/polyadenylation, indicating mechanistic conservation in formation of different mRNA 3' ends. We also unexpectedly identified the histone variants H2Av and H3.3A/B. In H2Av mutant cells, U7 snRNP remains active but fails to accumulate at the histone locus, suggesting there is a regulatory pathway that coordinates the production of variant and canonical histones that acts via localization of essential histone pre-mRNA processing factors.
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PMID: 18042462 [PubMed - indexed for MEDLINE]