A novel alternatively spliced viral mRNA transcribed in cells infected with human T cell leukemia virus type 1 is mainly responsible for expressing p21X protein

Orita, Satoshi; Saiga, Akihiko; Takagi, Shin; Tanaka, Tatsuro; Okumura, Koichi; Aono, Yuko; Hinuma, Yorio; Igarashi, Hisanaga

doi:10.1016/0014-5793(91)81402-t

Cited by 34 publications

(42 citation statements)

References 43 publications

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“…Since the natural occurring splice variant Rexp21 (Berneman et al, 1992;Bhat et al, 1993;Orita et al, 1991) was reported to be transdominant (Kubota et al, 1996) we constructed a Rexp21-GFP hybrid protein. Rexp21 is lacking the ®rst 78 N-terminal amino acids, including the RNAbinding domain and the nuclear localization signal (NLS).…”

Section: Localization Of Rex-gfp Hybrid Proteins In Living Human Cellsmentioning

confidence: 99%

Titration of cellular export factors, but not heteromultimerization, is the molecular mechanism of trans-dominant HTLV-1 Rex mutants

et al. 1999

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The HTLV-1 Rex protein is an essential shuttle protein required for nuclear export of unspliced and incompletely-spliced viral RNAs. Several trans-dominant (TD) mutant Rex proteins have been reported, however, the mechanism of trans-dominance is not known. We compared TD Rex mutants and found that a natural occurring Rex mutant, Rexp21, lacking the RNA binding domain, was highly TD and inhibited also HIV-1 Rev function. Using fusions to the green uorescent protein (GFP) we observed that Rexp21-GFP displayed a cytoplasmic localization but was actively shuttling between the nucleus and the cytoplasm in live human cells.

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Section: Localization Of Rex-gfp Hybrid Proteins In Living Human Cellsmentioning

confidence: 99%

Titration of cellular export factors, but not heteromultimerization, is the molecular mechanism of trans-dominant HTLV-1 Rex mutants

et al. 1999

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“…x protein itself have been detected in various HTLV-I-infected cell-lines and uncultured primary adult T-cell leukemic cells (Berneman et al, 1992;Furukawa et al, 1991;Orita et al, 1991). Although these data may indicate some involvement for p21…”

Section: Resultsmentioning

confidence: 94%

A cis-acting peptide signal in human immunodeficiency virus type I Rev which inhibits nuclear entry of small proteins

Kubota

Pomerantz

1998

Oncogene

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A peptide signal, which may control nucleo-cytoplasmic protein tracking, was newly identi®ed in human immunode®ciency virus type I (HIV-1) Rev, a lentiviral post-transcriptional transactivator. The sequence, in the amino-terminal portion of HIV-1 Rev, maintains a Rev mutant with a dysfunctional nuclear/nucleolar targeting signal outside of the nucleus, although this Rev molecule itself is small enough to pass through the nuclear pores. Transition of this sequence to the N-terminus of human T-lymphocytic leukemia/lymphoma virus type I (HTLV-I) p21 x , which is usually located evenly distributed throughout the cell, resulted in capture of p21x in the cytoplasm. Mutational analysis clari®ed that a 14 residue peptide sequence was sucient to display this inhibitory eect against nuclear entry. Furthermore, this HIV-1 Rev sequence was capable of inhibiting nuclear entry of a fragment of a human ribosomal protein, when it was fused to the carboxy terminus. The identi®ed nuclear entry inhibitory signal (NIS) contains a conserved hydrophilicity motif, which forms an amphipathic helix. Signi®cantly, this motif and its helical structure were shown to be important for NIS function and the HIV-1 Rev function itself. Possible roles for NIS as a molecular anchor are proposed herein.

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“…RT/TS-PCR was carried out as described previously (Orita et al, 1991). Briefly, 0-5 Izg of total RNA was annealed with 500 ng of a random hexadeoxynucleotide primer, reverse-transcribed using 15 units of AMV reverse transcriptase at 42 °C for 1 h, and 8.3 ~tl of 6 x PCR buffer (1 x PCR buffer consists of 16-6 mM-ammonium sulphate, 67 mM-Tris-HC1 pH 8.8 at 25 °C, 6-7 mM-magnesium chloride, 10 mM-2-mercaptoethanol, 7-7 p.M-EDTA and 170 ~tg/ml BSA), 5 p.1 each of 15 mM-dATP, 15 mM-dCTP, 15 mM-dGTP and 15 mM-TTP, and 1 pmol of the PCR primers PX1 and PX2 were then added to the reaction vessel to give a final volume of 50 p.l.…”

Section: Quantitative Rt/two Step Pcr (Rt/ts-pcr)mentioning

confidence: 99%

“…In contrast to this concept, we have recently discovered a novel, alternatively spliced mRNA capable of specifically expressing p21X (named p21X mRNA) in most HTLV-l-infected cell lines by using a highly sensitive method involving a polymerase chain reaction (PCR) coupled to reverse transcription (RT-PCR) (Orita et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

Human T cell leukaemia virus type 1 p21X mRNA: constitutive expression in peripheral blood mononuclear cells of patients with adult T cell leukaemia

Orita

Takagi

Saiga

et al. 1992

Journal of General Virology

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Although the p21X protein of human T cell leukaemia virus type 1 (HTLV-1) is generally thought to be expressed from a doubly spliced mRNA transcript • (tax/rex mRNA) that encodes the p40tax, p27rex and p21X proteins, we have shown previously that a novel, alternatively spliced mRNA transcript (p21X mRNA) is responsible for p21X production in HTLV-1-infected cell lines. In the present study, we analysed expression of p21X mRNA and tax/rex mRNA in uncultured and cultured peripheral blood mononuclear cells (PBMCs) from eight patients with adult T cell leukaemia by using a quantitative polymerase chain reaction coupled to reverse transcription. The results demonstrated that the expression of p21X mRNA occurs constitutively in all uncultured and cultured PBMCs, whereas the expression of tax/rex mRNA is inducible in the cultured PBMCs, as described previously. In uncultured and cultured PBMCs from the one specimen in which p21X mRNA was highly expressed, the p21X protein was detectable by Western blotting. On the other hand, p27rex protein was detectable only after cultivation. These findings indicate that p21 X mRNA is constitutively expressed in vivo and is responsible for production ofp21X protein.

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A novel alternatively spliced viral mRNA transcribed in cells infected with human T cell leukemia virus type 1 is mainly responsible for expressing p21X protein

Cited by 34 publications

References 43 publications

Titration of cellular export factors, but not heteromultimerization, is the molecular mechanism of trans-dominant HTLV-1 Rex mutants

Titration of cellular export factors, but not heteromultimerization, is the molecular mechanism of trans-dominant HTLV-1 Rex mutants

A cis-acting peptide signal in human immunodeficiency virus type I Rev which inhibits nuclear entry of small proteins

Human T cell leukaemia virus type 1 p21X mRNA: constitutive expression in peripheral blood mononuclear cells of patients with adult T cell leukaemia

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