Biochemical analysis of TREX complex recruitment to intronless and intron-containing yeast genes.
The TREX complex is involved in both transcription elongation and mRNA export and is recruited to nascent transcription complexes. We have examined Yra1p, Sub2p and Hpr1p recruitment to nine genes of varying lengths and transcription frequencies. All three proteins increase from the 5' to the 3' ends of the four intronless genes examined. A modified chromatin immunoprecipitation assay that includes an RNase step indicates that Sub2p is bound to nascent RNA, Yra1p is associated with both RNA and DNA, and Hpr1p is associated with DNA. Although Hpr1p is recruited similarly to both intronless and intron-containing genes, low Yra1p and Sub2p levels are present on a subset of intron-containing genes. The residual Yra1p and Sub2p recruitment is less RNA-associated, and this correlates with high levels of U1 SnRNP on these genes. These experiments support a model in which TREX is recruited via the transcription machinery and then Yra1p and Sub2p are transferred to the nascent RNA. On some intron-containing genes, retention and/or transfer of Yra1p and Sub2p to nascent RNA are inhibited.
Abruzzi
Katharine Compton
KC
Department of Biology, Howard Hughes Medical Institute, Brandeis University, Waltham, MA 02454, USA.
Lacadie
Scott
S
Rosbash
Michael
M
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D047369:Chromatin Immunoprecipitation; D004268:DNA-Binding Proteins / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D007438:Introns; D008954:Models, Biological; D009687:Nuclear Proteins / Q000378:metabolism*; D020365:RNA Helicases / Q000378:metabolism; D012326:RNA Splicing; D012331:RNA, Fungal / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C063494:HPR1 protein, S cerevisiae; D009687:Nuclear Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; C105887:YRA1 protein, S cerevisiae; D000251:Adenosine Triphosphatases; C027900:RNA-dependent ATPase; D020365:RNA Helicases