title: HTLV x gene mutants exhibit novel transcriptional regulatory phenotypes.
abstract: The human T-cell leukemia viruses, HTLV-I and HTLV-II, contain a gene, termed x, with transcriptional regulatory function. The properties of the x proteins were analyzed by constructing mutant genes containing site-directed deletions and point mutations. The results demonstrate that the amino terminal 17 amino acids of the x protein constitute part of a functional domain that is critical for the transcriptional activating properties of the protein. Within this region, substitution of a leucine residue for a proline residue results in major changes in the trans-activation phenotype of the protein. The mutant HTLV-II x protein, though incapable of activating the HTLV-II long terminal repeat, will block trans-activation of the HTLV-II long terminal repeat by the wild-type protein. The altered phenotype of this mutant suggests a potential negative regulatory function of the x protein.
mesh_terms: D017977:Deltaretrovirus / Q000235:genetics*; D005786:Gene Expression Regulation; D005814:Genes, Viral; D009154:Mutation; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D014157:Transcription Factors