Summary:We recently reported the finding of phylogenetically related HIV-1 BG intersubtype recombinant and G subtype nonrecombinant viruses circulating among injecting drug users in the region of Galicia in northwestern Spain. Here, we report the characterization of near full-length genome sequences of nine of these viruses (seven BG recombinant and two of nonrecombinant G subtype), obtained from epidemiologically unlinked individuals. Bootscan analysis reveals that six recombinant viruses share an identical mosaic structure, with two intersubtype breakpoints delimiting a B subtype segment comprising most of Env gp120 and the external portion of Env gp41, with the remaining portions of the genome being of subtype G, thus mimicking a pseudotype virion structure. The seventh BG recombinant virus exhibits breakpoints in env coincident with the other BG viruses but contains additional B subtype segments in gag and pol. In phylogenetic trees of complete genomes and of the B subtype segment of env, all seven BG viruses group in a monophyletic cluster. G subtype portions of the BG viruses group uniformly with the newly derived nonrecombinant G subtype viruses of Galicia in bootscan analysis, which points to the locally circulating G subtype strain as parental of the recombinants. These results allow us to define a new HIV-1 circulating recombinant form (CRFI4_BG), the first reported to originate in Western Europe.
E. Delgado and M. Thomson contributed equally to this study.
Address correspondence and reprint requests to Rafael Nájera, Instituto de Salud Carlos III, Ctra. Majadahonda-Pozuelo, Km. 2, 28220 Majadahonda, Madrid, Spain; e-mail: email@example.com
Manuscript received September 6, 2001; accepted December 18, 2001.
© 2002 by Lippincott Williams & Wilkins