title: Stable assembly of HIV-1 export complexes occurs cotranscriptionally.
abstract: The HIV-1 Rev protein mediates export of unspliced and singly spliced viral transcripts by binding to the Rev response element (RRE) and recruiting the cellular export factor CRM1. Here, we investigated the recruitment of Rev to the transcription sites of HIV-1 reporters that splice either post- or cotranscriptionally. In both cases, we observed that Rev localized to the transcription sites of the reporters and recruited CRM1. Rev and CRM1 remained at the reporter transcription sites when cells were treated with the splicing inhibitor Spliceostatin A (SSA), showing that the proteins associate with RNA prior to or during early spliceosome assembly. Fluorescence recovery after photobleaching (FRAP) revealed that Rev and CRM1 have similar kinetics as the HIV-1 RNA, indicating that Rev, CRM1, and RRE-containing RNAs are released from the site of transcription in one single export complex. These results suggest that cotranscriptional formation of a stable export complex serves as a means to ensure efficient export of unspliced viral RNAs.
authors.forename: Isabel
authors.initials: I
authors.lastname: Nawroth
authors.forename: Florian
authors.initials: F
authors.lastname: Mueller
authors.forename: Eugenia
authors.initials: E
authors.lastname: Basyuk
authors.forename: Nancy
authors.initials: N
authors.lastname: Beerens
authors.forename: Ulrik L
authors.initials: UL
authors.lastname: Rahbek
authors.forename: Xavier
authors.initials: X
authors.lastname: Darzacq
authors.forename: Edouard
authors.initials: E
authors.lastname: Bertrand
authors.forename: Jørgen
authors.initials: J
authors.lastname: Kjems
authors.forename: Ute
authors.initials: U
authors.lastname: Schmidt
mesh_terms: D017398:Alternative Splicing / Q000502:physiology; D001665:Binding Sites; D002478:Cells, Cultured; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D028884:Karyopherins / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D055503:Protein Multimerization; D055550:Protein Stability; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D014158:Transcription, Genetic / Q000502:physiology*; D054321:rev Gene Products, Human Immunodeficiency Virus / Q000378:metabolism*; D000097606:Exportin 1 Protein
chemical_list: D028884:Karyopherins; D046912:Multiprotein Complexes; D012367:RNA, Viral; D018160:Receptors, Cytoplasmic and Nuclear; D054321:rev Gene Products, Human Immunodeficiency Virus; D000097606:Exportin 1 Protein; C514860:rev protein, Human Immunodeficiency Virus-1
keywords: CRM1; HIV-1 Rev; nuclear export