A 5' splice site enhances the recruitment of basal transcription initiation factors in vivo.
Transcription and pre-mRNA splicing are interdependent events. Although mechanisms governing the effects of transcription on splicing are becoming increasingly clear, the means by which splicing affects transcription remain elusive. Using cell lines stably expressing HIV-1 or beta-globin mRNAs, harboring wild-type or various 5' splice site mutations, we demonstrate a strong positive correlation between splicing efficiency and transcription activity. Interestingly, a 5' splice site can stimulate transcription even in the absence of splicing. Chromatin immunoprecipitation experiments show enhanced promoter docking of transcription initiation factors TFIID, TFIIB, and TFIIH on a gene containing a functional 5' splice site. In addition to their promoter association, the TFIID and TFIIH components, TBP and p89, are specifically recruited to the 5' splice site region. Our data suggest a model in which a promoter-proximal 5' splice site via its U1 snRNA interaction can feed back to stimulate transcription initiation by enhancing pre-initiation complex assembly.
Damgaard
Christian Kroun
CK
Centre for mRNP Biogenesis and Metabolism, University of Aarhus, Aarhus, Denmark.
Kahns
Søren
S
Lykke-Andersen
Søren
S
Nielsen
Anders Lade
AL
Jensen
Torben Heick
TH
Kjems
Jørgen
J
D002460:Cell Line; D005914:Globins / Q000096:biosynthesis* / Q000235:genetics; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000502:physiology; D022821:RNA Splice Sites / Q000502:physiology*; D012326:RNA Splicing / Q000502:physiology*; D012342:RNA, Small Nuclear / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000502:physiology*
D046912:Multiprotein Complexes; D022821:RNA Splice Sites; D012342:RNA, Small Nuclear; D014157:Transcription Factors; C405483:U1 small nuclear RNA; D005914:Globins