YY1 Transcription Factor Down-regulates Expression of CCR5, a Major Coreceptor for HIV-1

Masako Moriuchi,Hiroyuki Moriuchi

doi:10.1074/jbc.m204980200

Abstract

Expression of CCR5, a major coreceptor for human immunodeficiency virus type 1 (HIV-1), is regulated by a number of transcription factors. Here we report that the YY1 transcription factor down-regulates CCR5 promoter activity and that overexpression of YY1 reduces cell surface CCR5 expression and infectibility by R5-HIV-1. Because YY1 also down-regulates promoter activities of CXCR4, another major coreceptor for HIV-1 and HIV-1 long terminal repeat, this transcription factor may play a critical role in the pathogenesis of HIV-1 disease.

Highlights

YY1 is a ubiquitous transcription factor that regulates a number of cellular and viral promoters, depending on the gene as well as the cell type in question
Overexpression of YY1 Down-regulates CCR5 Promoter—Because we and others have demonstrated that the YY1 transcription factor mediates a variety of effects on human immunodeficiency virus type 1 (HIV-1) infection, we wanted to investigate whether this transcription factor plays a role in CCR5 expression on CD4ϩ T cells, a target for HIV-1
In this study we have demonstrated that the YY1 transcription factor can down-regulate expression of CCR5 at the promoter level

Summary

EXPERIMENTAL PROCEDURES

Plasmids—Plasmids pGL-CCR5 and pGL-CCR5(Ϫ417) were described previously (8). Plasmid pGL-CCR5 (YY1-WT) contains the CCR5 promoter sequence spanning Ϫ607 to ϩ61 relative to the major transcription start site (TSS) (8), followed by the luciferase reporter gene in plasmid pGL3-basic (Promega Corp., Madison, WI). CD4ϩ T cell-enriched PBMC were stimulated with recombinant human interleukin-2 (IL-2) (100 units/ml) for 7 days. Transfection and Transient Expression Assays—Transfections of PBMC were performed using electroporation as described previously (14) or the Human T Cell NucleofectorTM kit (Amaxa Biosystems). Luciferase assays for transient expression assays were performed as described previously (14). Single-round Viral Infection and Flow Cytometric Analysis for Intracellular Expression of p24 Ag—The recombinant, replication-incompetent virus NL4 –3luc-RϪEϪ that had been complemented with R5 JR-FL Env was designated NL4 –3luc/JR-FL here and propagated as described previously (13). For intracellular p24 Ag staining, the transfected and (mock-)infected cells were washed once in phosphate-buffered saline containing 5%.

TABLE I Oligonucleotides used for gel mobility shift assays

RESULTS

DISCUSSION