Identification of p26Xb and p24Xb of human T-cell leukemia virus type II.

Human T-cell leukemia virus type II (HTLV-II) isolated from a T-cell variant of hairy cell leukemia contains gag, pol and env genes as well as a fourth gene termed X, which can code three major open reading frames Xa, Xb and Xc. Proteins with molecular masses of 26 kDa (p26Xb) and 24 kDa (p24Xb) encoded by the Xb open reading frame were identified with antisera directed against synthetic peptides corresponding to the N-terminal and C-terminal amino acid sequences deduced from the structure of the Xb open reading frame. More than half the Xb products were found to be located in the nuclear fraction of HTLV-II-infected cells.