characteristic features in common with the genome of other retroviruses: long terminal repeats (L TR), and coding regions for internal proteins (gag), for re- verse transcriptase (pol), and for glycosylated virion surface proteins (env), ar- ranged in the sequence gag, pol, env from the 5' to the 3' end of the genome. However, the HTL V genome also contains some specific features not shared with all other retroviruses: the LTR regions are unusually long (745 base pairs, with 298 base pairs constituting the R region), but unlike the long L TRs of mouse mammary tumor viruses, they do not...

The technique of microinjection along with viral genetics and molecular biology has proven useful in the correlation of retroviral polynucleotide structure with function. The advantage of this technique is the involvement of living cells where rare activities may be observed and where properties of living cells can be assayed. Future studies involving recombinant DNA molecules and the asso- ciation of proteins with nucleic acids promise to yield additional insight into the nucleotide sequences involved in the expression of viral activities. References Anderson SM, Chen JH (1981) In vitro...