Recognition of trimethylated histone H3 lysine 4 facilitates the recruitment of transcription postinitiation factors and pre-mRNA splicing.
Trimethylation of histone H3 on lysine 4 (H3K4me3) localizes near the 5' region of genes and is tightly associated with active loci. Several proteins, such as CHD1, BPTF, JMJD2A, and the ING tumor suppressor family, directly recognize this lysine methyl mark. However, how H3K4me3 recognition participates in active transcription remains poorly characterized. Here we identify specific CHD1-interacting proteins via H3K4me3 affinity purification, including numerous factors mediating postinitiation events. Conventional biochemical purification revealed a stable complex between CHD1 and components of the spliceosome. Depletion of CHD1 in extracts dramatically reduced splicing efficiency in vitro, indicating a functional link between CHD1 and the spliceosome. Knockdown of CHD1 and H3K4me3 levels by siRNA reduced association of U2 snRNP components with chromatin and, more importantly, altered the efficiency of pre-mRNA splicing on active genes in vivo. These findings suggest that methylated H3K4 serves to facilitate the competency of pre-mRNA maturation through the bridging of spliceosomal components to H3K4me3 via CHD1.
Department of Biochemistry, New York University School of Medicine, New York, NY 10016, USA.
Robert J
RJ
Sims
Scott
S
Millhouse
Chi-Fu
CF
Chen
Brian A
BA
Lewis
Hediye
H
Erdjument-Bromage
Paul
P
Tempst
James L
JL
Manley
Danny
D
Reinberg
D002843:Chromatin / Q000378:metabolism; D004265:DNA Helicases / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D006367:HeLa Cells; D006657:Histones / Q000378:metabolism*; D006801:Humans; D008239:Lysine / Q000378:metabolism*; D008745:Methylation; D008957:Models, Genetic; D010455:Peptides / Q000378:metabolism; D011485:Protein Binding; D012322:RNA Precursors / Q000378:metabolism*; D012326:RNA Splicing; D017413:Ribonucleoprotein, U2 Small Nuclear / Q000378:metabolism; D017381:Spliceosomes / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D002843:Chromatin; D004268:DNA-Binding Proteins; D006657:Histones; D010455:Peptides; D012322:RNA Precursors; D017413:Ribonucleoprotein, U2 Small Nuclear; D014157:Transcription Factors; C088049:splicing factor 3a; D004265:DNA Helicases; C080359:CHD1 protein, human; D008239:Lysine