The U5 sequence is a cis-acting repressive element for genomic RNA expression of human T cell leukemia virus type I.
The long terminal repeat (LTR) of HTLV-1 consists of U3-R-U5 and contains elements which regulate the viral gene expression. In addition to these elements, we found that the U5 sequence contained a repressive element in the gene expression. Sequential deletions of the LTR substantially increased CAT expression of a LTR-CAT construct. The repressive effect was also observed at RNA level on unspliced RNA, but not on spliced RNA. These differential effects suggest that the U5 element is a cis-acting RNA element, since splicing within the R segment removed the U5 element. In the context of HTLV-1 gene expression, the U5 element would repress expression of unspliced genomic RNA of HTLV-1, but not subgenomic RNA.
Seiki
M
M
Department of Viral Oncology, Cancer Institute, Tokyo, Japan.
Hikikoshi
A
A
Yoshida
M
M
D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis; D004742:Enhancer Elements, Genetic; D015967:Gene Expression Regulation, Viral; D015368:Human T-lymphotropic virus 1 / Q000235:genetics*; D006801:Humans; D012326:RNA Splicing; D012367:RNA, Viral / Q000096:biosynthesis*; D012091:Repetitive Sequences, Nucleic Acid; D015534:Trans-Activators / Q000235:genetics*; D015533:Transcriptional Activation
D012367:RNA, Viral; D015534:Trans-Activators; D015500:Chloramphenicol O-Acetyltransferase