| abstract |
A variant tax gene of bovine leukemia virus enhancing ability to induce replication of bovine leukemia virus or a retrovirus related to the bovine leukemia virus which encodes a variant gene product containing one or more mutations selected from the group consisting of substitution of the 240th Ser for Thr, substitution of the 247th Asp for Gly, substitution of the 251st Thr for Ala, substitution of the 258th Asp for Gly, substitution of the 261st His for Arg, substitution of the 261st His for Tyr, and substitution of the 265th Ser for Gly. |