Regulation of HTLV-II gene expression by Rex involves positive and negative cis-acting elements in the 5'long terminal repeat.
Regulation of human T-cell leukemia virus type II (HTLV-II) gene expression by the trans-acting viral protein, Rex, is mediated through specific cis-acting sequences in the HTLV-II long terminal repeat (LTR). Augmentation of 5' LTR-linked gene expression by Rex requires two distinct cis-acting elements: one termed the "Rex-responsive element" (RxRE), which allows Rex to overcome the inhibitory effect of a second, termed the "cis-acting repressive sequences" (CRS). The HTLV-II RxRE is located between nt +91 and +317 relative to the cap site in the R/U5 region of the 5'LTR, and the HTLV-II CRS is contained within the RxRE from nt +208 to +317, which is downstream of the splice donor site, in the R/U5 region of the 5' LTR. Deletion of the CRS results in significantly increased cytoplasmic levels of LTR-linked mRNA independent of the presence of Rex. Our results show that Rex acts post-transcriptionally and induces a shift from nucleus to cytoplasm of gag/pol mRNA, the only HTLV-II mRNA that contains both the RxRE and the CRS in the 5' LTR-derived leader sequence.
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Department of Medicine, UCLA School of Medicine.
Chen
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Arrigo
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Ruland
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Allogiamento
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Chin
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Rosenblatt
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D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D015967:Gene Expression Regulation, Viral; D016370:Gene Products, rex / Q000235:genetics*; D016355:Genes, pX; D015367:Human T-lymphotropic virus 2 / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012326:RNA Splicing; D012333:RNA, Messenger / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D012091:Repetitive Sequences, Nucleic Acid
D016370:Gene Products, rex; D012333:RNA, Messenger