The goal of this research is to understand the mechanisms whereby the Tat protein and TAR element of human immunodeficiency virus (HIV-1) affect viral gene expression, and how these moieties contribute to viral pathogenicity. Tat interacts with transcripts of the TAR region to transactivate expression of genes linked to the HIV-1 long terminal repeat (LTR). In an adenovirus-derived model system, we have shown that this transactivation is bi-modal: transcriptional initiation and the processivity of RNA polymerase are both increased. The elongation effect predominates when the basal rate of transcriptional initiation at the HIV-1 LTR is elevated, either by general transactivators with which Tat synergizes in the adenovirus system, or by other genetic elements such as the SV40 replication origin in a transient expression system employing replicating plasmids. We propose to extend these findings to cell types that reflect the normal hosts for HIV-1 infection, as well as proviral cell lines, and to analyze the mechanism of transactivation by Tat in greater depth. Mechanistic studies will be pursued in vivo and in a cell-free transcription system in vitro. We will explore the roles played in Tat-transactivation by LTR elements other than TAR, and investigate the influence of the SV40 origin of DNA replication on transcription from the HIV LTR. Finally, we will address the possibility that transcripts of the TAR region affect translational efficiency and will examine the mechanisms underlying this effect.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI031802-05
Application #
2066732
Study Section
AIDS and Related Research Study Section 3 (ARRC)
Project Start
1992-02-01
Project End
1996-08-31
Budget Start
1996-02-01
Budget End
1996-08-31
Support Year
5
Fiscal Year
1996
Total Cost
Indirect Cost
Name
Cold Spring Harbor Laboratory
Department
Type
DUNS #
065968786
City
Cold Spring Harbor
State
NY
Country
United States
Zip Code
11724
Hoque, Mainul; Tian, Bin; Mathews, Michael B et al. (2005) Granulin and granulin repeats interact with the Tat.P-TEFb complex and inhibit Tat transactivation. J Biol Chem 280:13648-57
Reza, Syed M; Shen, Lin-Ming; Mukhopadhyay, Rupa et al. (2003) A naturally occurring substitution in human immunodeficiency virus Tat increases expression of the viral genome. J Virol 77:8602-6
Hoque, Mainul; Young, Tara M; Lee, Chee-Gun et al. (2003) The growth factor granulin interacts with cyclin T1 and modulates P-TEFb-dependent transcription. Mol Cell Biol 23:1688-702
Young, Tara M; Wang, Qi; Pe'ery, Tsafi et al. (2003) The human I-mfa domain-containing protein, HIC, interacts with cyclin T1 and modulates P-TEFb-dependent transcription. Mol Cell Biol 23:6373-84
Reza, Syed M; Rosetti, Mihaela; Mathews, Michael B et al. (2003) Differential activation of Tat variants in mitogen-stimulated cells: implications for HIV-1 postintegration latency. Virology 310:141-56
Ramanathan, Y; Rajpara, S M; Reza, S M et al. (2001) Three RNA polymerase II carboxyl-terminal domain kinases display distinct substrate preferences. J Biol Chem 276:10913-20
Ramanathan, Y; Reza, S M; Young, T M et al. (1999) Human and rodent transcription elongation factor P-TEFb: interactions with human immunodeficiency virus type 1 tat and carboxy-terminal domain substrate. J Virol 73:5448-58
Gunnery, S; Ma, Y; Mathews, M B (1999) Termination sequence requirements vary among genes transcribed by RNA polymerase III. J Mol Biol 286:745-57
Greenberg, M E; Mathews, M B (1997) Effects of heterologous downstream sequences on the activity of the HIV-1 promoter and its response to Tat. Nucleic Acids Res 25:5017-24
Pe'ery, T; Mathews, M B (1997) Synthesis and purification of single-stranded RNA for use in experiments with PKR and in cell-free translation systems. Methods 11:371-81

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