Genetic and functional characterization of the LTR of HIV-1 subtypes A and C circulating in India.

Genetic analysis of HIV-1 sequences circulating in different parts of India have shown that the predominant proportion of HIV-1 subtypes circulating in India is type C and a small fraction are subtypes A, B, E, and CRFs. We sequenced the HIV-1 LTR promoter region of seven subtype C and five subtype A isolates obtained from two major cities in India. Sequence analysis of the complete promoter and TAR regions revealed conserved subtype-specific variability in several major binding sites. Three NF-κB sites were present in all subtype C isolates and two isolates contained an insertion in the MFNLP. The transcriptional activity of one of these isolates may have been hindered due to this insertion. Despite the apparent variability between the LTRs we did not observe any significant difference in the transcriptional activity between subtype C and subtype A. To our knowledge, this is the first study characterizing the genetic structure and functional attributes of subtype A LTRs from India.