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A transcriptional enhancer sequence of HTLV‐I is responsible for trans‐activation mediated by p40 chi HTLV‐I.
Author(s) -
Fujisawa J.,
Seiki M.,
Sato M.,
Yoshida M.
Publication year - 1986
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1986.tb04272.x
Subject(s) - enhancer , long terminal repeat , sequence (biology) , gene , transcription (linguistics) , microbiology and biotechnology , mutant , biology , human immunodeficiency virus (hiv) , genetics , virology , physics , transcription factor , gene expression , philosophy , linguistics
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.