The RNA processing exosome is linked to elongating RNA polymerase II in Drosophila.
The RNA polymerase II elongation complex contains several factors that facilitate transcription elongation and catalyse the processing of precursor messenger RNAs (pre-mRNAs). The conserved elongation factor Spt6 is recruited rapidly and robustly to sites of active transcription. Here we show that Drosophila Spt6 (dSpt6) co-purifies with the exosome, a complex of 3' to 5' exoribonucleases that is implicated in the processing of structural RNA and in the degradation of improperly processed pre-mRNA. Immunoprecipitation assays of Drosophila nuclear extracts show that the exosome also associates with the elongation factor dSpt5 and RNA polymerase II. In vivo, exosome subunits colocalize with dSpt6 at transcriptionally active loci on polytene chromosomes during normal development and are strongly recruited to heat-shock loci on gene induction. At higher resolution, chromatin immunoprecipitation analysis shows that the exosome is recruited to transcriptionally active units of heat-shock genes. These data provide a physical basis for the hypothesis that exosome-mediated pre-mRNA surveillance accompanies transcription elongation.
Andrulis
Erik D
ED
Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA. eda4@cornell.edu
Werner
Janis
J
Nazarian
Arpi
A
Erdjument-Bromage
Hediye
H
Tempst
Paul
P
Lis
John T
JT
D000818:Animals; D002460:Cell Line; D002868:Chromosomal Proteins, Non-Histone; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology / Q000201:enzymology* / Q000235:genetics*; D005095:Exoribonucleases / Q000378:metabolism; D005786:Gene Expression Regulation; D017344:Genes, Insect / Q000235:genetics; D006360:Heat-Shock Proteins / Q000235:genetics; D046911:Macromolecular Substances; D009687:Nuclear Proteins / Q000378:metabolism; D010445:Peptide Elongation Factors / Q000235:genetics / Q000378:metabolism*; D011233:Precipitin Tests; D011485:Protein Binding; D021122:Protein Subunits; D012319:RNA Polymerase II / Q000378:metabolism*; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D035602:Transcriptional Elongation Factors / Q000378:metabolism
D002868:Chromosomal Proteins, Non-Histone; D029721:Drosophila Proteins; D006360:Heat-Shock Proteins; D046911:Macromolecular Substances; D009687:Nuclear Proteins; D010445:Peptide Elongation Factors; D021122:Protein Subunits; D012322:RNA Precursors; C470423:Spt6 protein, Drosophila; D035602:Transcriptional Elongation Factors; C069940:SPT5 transcriptional elongation factor; D012319:RNA Polymerase II; D005095:Exoribonucleases