Transcription through the HIV-1 nucleosomes: effects of the PBAF complex in Tat activated transcription.
The SWI/SNF complex remodels nucleosomes, allowing RNA Polymerase II access to the HIV-1 proviral DNA. It has not been determined which SWI/SNF complex (BAF or PBAF) remodels nucleosomes at the transcription start site. These complexes differ in only three subunits and determining which subunit(s) is required could explain the regulation of Tat activated transcription. We show that PBAF is required for chromatin remodeling at the nuc-1 start site and transcriptional elongation. We find that Baf200 is required to ensure activation at the LTR level and for viral production. Interestingly, the BAF complex was observed on the LTR whereas PBAF was present on both LTR and Env regions. We found that Tat activated transcription facilitates removal of histones H2A and H2B at the LTR, and that the FACT complex may be responsible for their removal. Finally, the BAF complex may play an important role in regulating splicing of the HIV-1 genome.
Easley
Rebecca
R
National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, VA 20110, USA. rleasl@gmail.com
Carpio
Lawrence
L
Dannenberg
Luke
L
Choi
Soyun
S
Alani
Dowser
D
Van Duyne
Rachel
R
Guendel
Irene
I
Klase
Zachary
Z
Agbottah
Emmanuel
E
Kehn-Hall
Kylene
K
Kashanchi
Fatah
F
D002460:Cell Line; D002478:Cells, Cultured; D002843:Chromatin / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D015967:Gene Expression Regulation, Viral; D016325:HIV Long Terminal Repeat / Q000235:genetics; D015497:HIV-1 / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000821:virology; D009707:Nucleosomes / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000378:metabolism*
D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D009707:Nucleosomes; C445179:SWI-SNF-B chromatin-remodeling complex; D014157:Transcription Factors; D054322:tat Gene Products, Human Immunodeficiency Virus