English: A diagram of Rev/RRE function, HIV-1 RNA export. In the early phase (top), transcribed viral RNAs (9kb) are spliced down to 2kb before export. One of these 2kb messages is translated to produce Rev which is then imported into the nucleus. In the late phase (bottom), Rev binds the RRE of newly transcribed RNAs before splicing and exports the unspliced (9kb) and partially spliced (4kb) messages to the cytoplasm. Translation of these messages produces late stage viral proteins. 9 kb messages can also serve as genomes for new virions.