Specific interaction of the human immunodeficiency virus Rev protein with a structured region in the env mRNA.

A region of potential complex secondary structure within the human immunodeficiency virus env mRNA has been implicated in Rev-mediated export of viral structural mRNAs from the nucleus to the cytoplasm. By using an RNase protection gel-mobility-shift assay, we demonstrate that purified Rev protein forms a stable complex with this Rev-responsive RNA. RNAs with mutations designed to disrupt formation of a predicted stem structure no longer interact with Rev. However, Rev binding is restored upon annealing of the two complementary RNAs that make up the stem. These results suggest that direct interaction of Rev with the Rev-responsive element could facilitate transport of human immunodeficiency virus structural mRNAs from the nucleus to the cytoplasm.