A transcriptional enhancer sequence of HTLV-I is responsible for trans-activation mediated by p40 chi HTLV-I.
Human T-cell leukemia virus type I (HTLV-I) contains a unique sequence pX that is located between env and the 3' long terminal repeat (LTR) and codes for three pX proteins, p40 chi, pp27 chi-III and pp21 chi-III. One of these proteins, p40 chi, was previously shown to activate transcription from the LTR in a trans-acting manner, which suggested that it activated some cellular genes involved in leukemogenesis. In this study, the sequences in the LTR responsible for this trans-activation were analyzed. Construction of deletion mutants of the LTR in pLTR-CAT and measurement of their activities in trans-activated expression of the CAT gene showed that sequences upstream of the TATA box were responsible for the trans-activation mediated by p40 chi. The active unit was identified as an enhancer sequence containing direct repeats by inserting it into an enhancer-minus SV40 promoter. Thus, it was concluded that an enhancer sequence in HTLV-I LTR is responsible, at least in part, for transcriptional trans-activation mediated by the viral product p40 chi.
D000123:Acetyltransferases / Q000235:genetics; D001483:Base Sequence; D015500:Chloramphenicol O-Acetyltransferase; D002872:Chromosome Deletion; D004262:DNA Restriction Enzymes; D017977:Deltaretrovirus / Q000235:genetics* / Q000254:growth & development; D004742:Enhancer Elements, Genetic; D005796:Genes; D005809:Genes, Regulator; D005814:Genes, Viral; D006801:Humans; D009154:Mutation; D010957:Plasmids; D011401:Promoter Regions, Genetic; D013539:Simian virus 40 / Q000235:genetics; D014158:Transcription, Genetic; D014162:Transfection; D014764:Viral Proteins / Q000235:genetics*; D014775:Virus Activation
D014764:Viral Proteins; D000123:Acetyltransferases; D015500:Chloramphenicol O-Acetyltransferase; D004262:DNA Restriction Enzymes