Transmission of human immunodeficiency type 1 viruses with intersubtype recombinant long terminal repeat sequences

Retroviruses such as human immunodeficiency virus type 1 (HIV-1) contain two RNA strands per virion, and recombination can occur frequently during reverse transcription. Recombination may occur between HIV-1 genomes of the same subtype or among genomes of two or more distinct subtypes present in an individual. In the current study, we found that recombinatorial events were not limited to viral structural genes such as gag and env, but rather, recombination could likewise occur within the 5' long terminal repeat (LTR). Intersubtype recombinant LTRs among HIV-1 subtypes A, C, and D were found in Tanzanian infants. By introducing novel LTR sequences, these recombinant LTR viruses may further increase the adaptive potential and fitness of HIV-1. (C) 1999 Academic Press.