Dayton Andrew I.; Terwilliger, Ernest F.; Potz, Joseph; Kowalski, Mark; Sodroski, Joseph G.; Haseltine, William A.Journal of Acquired Immune Deficiency Syndromes: October 1988 ORIGINAL ARTICLE: PDF Only Free Abstract Expression of high levels of the structural proteins of the human immunodeficiency virus type 1 (HIV-1) requires the presence of two regulatory genes, the trans-activator (tat), and the regulator of virion protein expression (rev, previously called art or trs). The experiments described here show that expression of virion proteins is dependent upon a small region located in the envelope gene called the cis-acting antirepression sequence (CAR). The CAR region of the envelope sequence is both necessary and sufficient for rev-dependent capsid protein expression. The experiments also show that a defect in either rev or CAR results in a dramatic decrease in the accumulation of the genomic and envelope mRNAs and an overproduction of more extensively spliced viral mRNA species. © Lippincott-Raven Publishers.