Abstract
Searching the protein sequence database for amino acid sequences homologous to the
x-lor sequence in the pX region of human T-cell leukemia virus types I and II (HTLV-I/II), we found that there is a region of 38 amino acids where the murine interleukin 3 (IL-3) sequence has a 40% homology with the
x-lor sequence. A statistical analysis shows that this homology is highly significant with a probability of 1.57 × 10
−10. The biological implication of this homology is discussed.