Constitutive expression of human immunodeficiency virus (HIV) nef protein in human astrocytes does not influence basal or induced HIV long terminal repeat activity

Since human immunodeficiency virus (HIV) nef has been suggested to exert regulatory effects on HIV long terminal repeat (LTR) activity, we transiently transfected HIV LTR chloramphenicol acetyltransferase or luciferase expression vectors into a human astrocytoma clone (U-373nef) that constitutively expresses the HIV nef gene. In these cells, basal HIV LTR activity, as well as tumor necrosis factor-induced or tat-driven activity, was similar to that in control cells. Lack of any detectable effect of HIV nef on LTR activity was not the result of mutations in integrated nef DNA, as was shown by polymerase chain reaction. These data suggest that the role of nef in HIV genome transcription does not necessarily involve a direct influence on HIV LTR activity.