The Chromatin Remodeler ISW1 Is a Quality Control Factor that Surveys Nuclear mRNP Biogenesis

Chromatin dynamics play an essential role in regulating DNA transaction processes, but it is unclear whether transcription-associated chromatin modifications control the mRNA ribonucleoparticles (mRNPs) pipeline from synthesis to nuclear exit. Here, we identify the yeast ISW1 chromatin remodeling complex as an unanticipated mRNP nuclear export surveillance factor that retains export-incompetent transcripts near their transcription site. This tethering activity of ISW1 requires chromatin binding and is independent of nucleosome sliding activity or changes in RNA polymerase II processivity. Combination of in vivo UV-crosslinking and genome-wide RNA immunoprecipitation assays show that Isw1 and its cofactors interact directly with premature mRNPs. Our results highlight that the concerted action of Isw1 and the nuclear exosome ensures accurate surveillance mechanism that proofreads the efficiency of mRNA biogenesis. [Display omitted] •The chromatin remodeling complex ISW1 controls nuclear poly(A) RNA accumulation•Inactivation of ISW1 rescues nuclear export of improper mRNPs and resulting genetic instability•Isw1 participates in mRNP surveillance•Isw1 interacts with nuclear mRNPs A chromatin remodeling complex retains premature mRNPs in proximity to their transcription site, ensuring an accurate surveillance mechanism that proofreads the efficiency of mRNA biogenesis.