title: Negative elongation factor NELF represses human immunodeficiency virus transcription by pausing the RNA polymerase II complex.
abstract: Human immunodeficiency virus (HIV) transcription requires virally encoded Tat and the P-TEFb protein complex, which together associate with the Tat-activating region, a structured region in the nascent transcript. P-TEFb phosphorylates Proteins in the transcription elongation complex, including RNA polymerase II (pol II), to stimulate elongation and to overcome premature termination. However, the status of the elongation complex on the HIV long terminal repeat (LTR) in a repressed state is not known. Chromatin immunoprecipitation demonstrated that NELF, a negative transcription elongation factor, was associated with the LTR. Depleting NELF increased processive HIV transcription and replication. Mapping pol II on the LTR showed that pol II was paused and that NELF depletion released pol II. Decreasing NELF also correlated with displacement of a positioned nucleosome and increased acetylation of histone H4, suggesting coupling of transcription elongation and chromatin remodeling. Previous work has indicated that the Tat-activating region plays a critical role in regulating transcription from the LTR. Our results reveal an earlier stage, mediated by NELF, when repression occurs at the HIV LTR.
authors: Center of Molecular Immunology and Infectious Diseases, Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors: Zhiqiang
authors: Z
authors: Zhang
authors: Alicia
authors: A
authors: Klatt
authors: David S
authors: DS
authors: Gilmour
authors: Andrew J
authors: AJ
authors: Henderson
mesh_terms: D001483:Base Sequence; D047369:Chromatin Immunoprecipitation; D017931:DNA Primers; D006678:HIV / Q000235:genetics*; D016325:HIV Long Terminal Repeat; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D012319:RNA Polymerase II / Q000378:metabolism*; D034741:RNA, Small Interfering; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic / Q000502:physiology*
chemical_list: D017931:DNA Primers; D034741:RNA, Small Interfering; D014157:Transcription Factors; C118437:negative elongation factor; D012319:RNA Polymerase II