Cell-specific Regulation of TRBP1 Promoter by NF-Y Transcription Factor in Lymphocytes and Astrocytes
- 3 February 2006
- journal article
- Published by Elsevier BV in Journal of Molecular Biology
- Vol. 355 (5), 898-910
- https://doi.org/10.1016/j.jmb.2005.11.026
Abstract
HIV-1 viral production is restricted intracellularly in astrocytes compared with lymphocytes due to the limited expression of viral structural proteins. The poor translation of HIV-1 mRNA and consequent limited virion production can be restored by overexpression of TRBP proteins in the astrocytoma U251MG cells. TRBP1 and TRBP2 are double-stranded RNA binding proteins that increase HIV-1 gene expression. Both proteins are produced from a single gene that possesses two independent promoters and an alternative first exon. Endogenous expression is restricted in astrocytes due to limited TRBP promoter expression compared to lymphocytes. We examined the transcriptional regulation of TRBP1 and TRBP2 by in vivo genomic footprinting in the lymphocytic Jurkat and in the astrocytic U251MG cells. We identified one AP4 and one AP2-binding site that regulate the TRBP2 promoter in both cell types, and one Sp1 and two CCAAT-binding sites that control TRBP1 expression. Mutations in the TRBP1 promoter modulate its expression specifically in Jurkat and in U251MG. The analysis of the CCAAT-390 site by EMSA and by ChIP demonstrates that NF-Y/CBF transcription factor binds specifically to the promoter in vitro and in vivo. Furthermore, each NF-Y subunit was more highly expressed in the lymphocytic cells, compared to astrocytic cells. An NF-YA trans-dominant mutant decreased TRBP1 promoter expression fourfold in Jurkat cells, thus demonstrating the functional importance of NF-Y factors in lymphocytes. These studies suggest that the cell specifity of HIV-1 expression and replication may be regulated, in part, through the control of TRBP1 expression.Keywords
This publication has 58 references indexed in Scilit:
- TRBP, a regulator of cellular PKR and HIV‐1 virus expression, interacts with Dicer and functions in RNA silencingEMBO Reports, 2005
- TRBP recruits the Dicer complex to Ago2 for microRNA processing and gene silencingNature, 2005
- Chromatin Immunoprecipitation (ChIP) on Chip Experiments Uncover a Widespread Distribution of NF-Y Binding CCAAT Sites Outside of Core PromotersPublished by Elsevier BV ,2005
- The pleiotropic functions of the Y‐box‐binding protein, YB‐1BioEssays, 2003
- Dissection of functional NF-Y-RFX cooperative interactions on the MHC class II Ea promoterJournal of Molecular Biology, 2000
- Partial characterization of the CCAAT box in the promoter of the hIGFBP-1 gene: interaction with negatively acting transcription factors in decidualized human endometrial stromal cellsMolecular and Cellular Endocrinology, 2000
- Nuclear Factor Y (NF-Y) and Cellular SenescenceExperimental Cell Research, 1999
- NF-Y histone fold α1 helices help impart CCAAT specificityJournal of Molecular Biology, 1999
- Processing of Amyloid Precursor Protein in Human Primary Neuron and Astrocyte CulturesJournal of Neurochemistry, 1997
- Characterization of a Human TAR RNA-Binding Protein That Activates the HIV-1 LTRScience, 1991