Amino acid sequence analysis of HTLV ORF-I from ex vivo proviral DNA samples from HTLV-1–infected individuals. (A) Amino acid sequence alignment for p12^I variants from ex vivo proviral DNA samples from HTLV-1–infected individuals. DNA provirus fragment corresponding to ORF-I was amplified by PCR from PBMCs of 9 new patients, and the putative amino acids sequence of p12^I was compared with previously published p12^I sequence from our and other laboratories.^3,23-28  Consensus sequence is based on cosmopolitan type B samples (proline at position 23). Sequences V1-V24 are cosmopolitan type B variants and sequences V25-V65 are cosmopolitan type A variants (serine at position 23). The number of identical samples for each variant is given in the right column. Matches identical to the consensus sequences are represented by “.”; nonidentical matches are either in lowercase (if similar residues) or capital letters. There are 4 variants (V6, V9, V30, and V36) with premature termination represented by “−”. The shaded sequences indicate a cluster of changes proximal to the second proteolytic cleavage site. The 9 samples amplified with the primers described in “Methods” belong to variants V29, V46, V48-52 (1 sample each), and V34 (2 samples).