Citation
- Authors: Eilebrecht, S., Le Douce, V., Riclet, R., Targat, B., Hallay, H., Van Driessche, B., Schwartz, C., Robette, G., Van Lint, C., Rohr, O., Benecke, A. G.
- Year: 2014
- Journal: Nucleic Acids Res 42 4962-71
- Applications: in vitro / shRNA plasmid / jetPRIME
- Cell types:
- Name: CHME5
- Name: CMEH3
- Name: HEK-293
Description: Human embryonic kidney Fibroblast
Known as: HEK293, 293
Abstract
Active positive transcription elongation factor b (P-TEFb) is essential for cellular and human immunodeficiency virus type 1 (HIV-1) transcription elongation. CTIP2 represses P-TEFb activity in a complex containing 7SK RNA and HEXIM1. Recently, the inactive 7SK/P-TEFb small nuclear RNP (snRNP) has been detected at the HIV-1 core promoter as well as at the promoters of cellular genes, but a recruiting mechanism still remains unknown to date. Here we show global synergy between CTIP2 and the 7SK-binding chromatin master-regulator HMGA1 in terms of P-TEFb-dependent endogenous and HIV-1 gene expression regulation. While CTIP2 and HMGA1 concordingly repress the expression of cellular 7SK-dependent P-TEFb targets, the simultaneous knock-down of CTIP2 and HMGA1 also results in a boost in Tat-dependent and independent HIV-1 promoter activity. Chromatin immunoprecipitation experiments reveal a significant loss of CTIP2/7SK/P-TEFb snRNP recruitment to cellular gene promoters and the HIV-1 promoter on HMGA1 knock-down. Our findings not only provide insights into a recruiting mechanism for the inactive 7SK/P-TEFb snRNP, but may also contribute to a better understanding of viral latency.