Functional activation of the long terminal repeat of human T-cell leukemia virus type I by a trans-acting factor.
Promoter function for gene expression of the long terminal repeat (LTR) of human T-cell leukemia virus type I (HTLV-I) was studied by constructing plasmids containing the LTR sequence. The gene encoding chloramphenicol acetyltransferase (CATase) was linked to an HTLV-I LTR sequence (pLTR-CAT) by replacing the simian virus 40 promoter in plasmid pSV2-CAT with the LTR sequence. The transient CATase activities of cells transfected with the plasmids were compared. The results are summarized as follows: The HTLV LTR was active even in an epithelial cell line, with efficiency similar to that of the simian virus 40 promoter. pLTR-CAT expressed high CATase activity, 40-200 times that expressed by pSV2-CAT, in HTLV-I-infected T-cell lines, such as the human cell lines MT-2 and HUT-102, or in HTLV-I-infected rat cell lines. This enhanced activity of the LTR seems to be associated with HTLV gene expression, since only low activity of pLTR-CAT was observed in the HTLV-infected cell line MT-1, in which only a small percent of cells express viral antigens. In HTLV-infected rat cell lines, the pX-encoded protein p40x was the only viral protein detected. Thus, we suggest that p40x is the factor associated directly or indirectly with the enhanced activity of the LTR.
Fujisawa
J
J
Seiki
M
M
Kiyokawa
T
T
Yoshida
M
M
D000123:Acetyltransferases / Q000235:genetics; D000818:Animals; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase; D004279:DNA, Viral / Q000235:genetics*; D017977:Deltaretrovirus / Q000235:genetics*; D005786:Gene Expression Regulation; D005814:Genes, Viral; D006801:Humans; D009876:Operon; D010957:Plasmids; D051381:Rats; D012091:Repetitive Sequences, Nucleic Acid; D014764:Viral Proteins / Q000235:genetics
D004279:DNA, Viral; D014764:Viral Proteins; D000123:Acetyltransferases; D015500:Chloramphenicol O-Acetyltransferase