Modulation of HIV transcription by CD8(+) cells is mediated via multiple elements of the long terminal repeat.
HIV replication and LTR-mediated gene expression can be modulated by CD8(+) cells in a cell type-dependent manner. We have previously shown that supernatant fluids of activated CD8(+) cells of HIV-infected individuals suppress long terminal repeat (LTR)-mediated transcription of HIV in T cells while enhancing transcription in monocytic cells. Here, we have examined the effect of culture of T cells and monocytic cells with CD8(+) supernatant fluids, and subsequent binding of transcription factors to the HIV-1 LTR. In transfections using constructs in which NF kappa B or NFAT-1 sites were mutated, the LTR retained the ability to respond positively to culture with CD8 supernatant fluid in monocytic cells. Nuclear extracts prepared from both Jurkat T cells and U38 monocytic cells cultured with CD8(+) cell supernatant fluid demonstrated increased binding to the HIV-1 LTR at an AP-1 site which overlapped the chicken ovalbumin upstream promoter (COUP) site. In monocytic cells, increased binding activity was observed at the NF kappa B sites of the LTR. In contrast, an inhibition in binding at the NF kappa B sites was observed in Jurkat cells. Examination of two NFAT-1 sites revealed enhanced binding at - 260 to - 275 bp in U38 cells which was reduced by cellular activation. PMA and ionomycin-induced binding at a second NFAT-1 site (- 205 to - 216 bp) was abrogated by CD8(+) cell supernatant fluid in T cells. These results, taken together, suggest that factors present in CD8(+) supernatant fluids may act through several sites of the LTR to modulate transcription in a cell type-dependent manner.
Maslove
D M
DM
Centre for Molecular Medicine, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.
Ni
L W
LW
Hawley-Foss
N C
NC
Badley
A D
AD
Copeland
K F
KF
D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D004268:DNA-Binding Proteins / Q000378:metabolism; D015967:Gene Expression Regulation, Viral; D016325:HIV Long Terminal Repeat; D015497:HIV-1 / Q000235:genetics* / Q000276:immunology; D006801:Humans; D019169:Jurkat Cells; D016328:NF-kappa B / Q000378:metabolism; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D016328:NF-kappa B; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D014157:Transcription Factors