Human T-lymphotropic virus 1

Molecular biology

VIRION

Enveloped. Spherical to pleomorphic, about 80-100 nm in diameter.

GENOME

Monopartite, linear, dimeric, ssRNA(+) genome of 8,5 kb, with a 5’-cap and a 3’poly-A tail. There are two long terminal repeats (LTRs) of about 600nt long at the 5’ and 3’ ends. The LTRs contain the U3, R, and U5 regions. There are also a primer binding site (PBS) at the 5’end and a polypurine tract (PPT) at the 3’end.

GENE EXPRESSION

The integrated provirus utilizes the promoter elements in the 5’LTR to drive transcription. This gives rise to the unspliced full length mRNA that will serve as genomic RNA to be packaged into virions or used as a template for translation of gag, gag-pro (1 ribosomal frameshift), and gag-pro-pol (2 ribosomal frameshifts) polyproteins. The singly spliced mRNA encodes env that is cleaved into SU and TM envelope proteins. Completely spliced mRNAs encode Rex and Tax. Rex escorts unspliced and singly spliced RNAs out of the nucleus of infected cells. Tax is a transcriptional activator that activates viral and cellular genes. Four accessory proteins p27I, p12I, p13II and p30II are also produced by alternative splicing of ORFs I and II.

REPLICATION

NUCLEAR

Lytic replication:

  1. Virus attaches to host receptors through the SU glycoprotein. TM glycoprotein mediates fusion with cell membrane.
  2. Internalization and uncoating.
  3. ssRNA(+) genome is copied into a linear dsDNA molecule by the reverse transcriptase.
  4. Nuclear entry of the viral dsDNA which is covalently and randomly integrated into the cell’s genome by the integrase (=provirus).
  5. Transcription of provirus by Pol II produces viral spliced and unspliced RNAs.
  6. Translation of fully spliced viral RNAs produces tax and rex proteins.
  7. Rex mediates nuclear export of the uncompletely spliced RNAs.
  8. Translation of unspliced viral RNAs produces Env, Gag, Gag-Pro and Gag-Pro-Pol polyproteins.
  9. Assembly of the virion at the host cellular membrane and packaging of the viral RNA genome.
  10. Budding through the plasma membrane and release of the virions.
  11. Proteolytic processing of the precursors polyproteins by viral protease and maturation of the virions.

Latent replication : replication as a provirus integrated in the host chromosome.

Matching UniProtKB/Swiss-Prot entries

31 entries grouped by protein (browse by keywords)

All proteins are shown (view only 18 complete proteome entries)

Envelope glycoprotein gp62 (Env polyprotein)

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ENV_HTL1CHuman T-cell leukemia virus 1 (isolate Caribbea HS-35 subtype A) (HTLV-1) reference strain
ENV_HTL1NHuman T-cell leukemia virus 1 (isolate Caribbea CH subtype A) (HTLV-1)
ENV_HTL1LHuman T-cell leukemia virus 1 (isolate Melanesia mel5 subtype C) (HTLV-1)
ENV_HTL1FHuman T-cell leukemia virus 1 (isolate Zaire EL subtype B) (HTLV-1)
ENV_HTL1AHuman T-cell leukemia virus 1 (strain Japan ATK-1 subtype A) (HTLV-1)
ENV_HTL1MHuman T-cell leukemia virus 1 (strain Japan MT-2 subtype A) (HTLV-1)

Gag polyprotein (Pr53Gag)

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GAG_HTL1CHuman T-cell leukemia virus 1 (isolate Caribbea HS-35 subtype A) (HTLV-1) reference strain
GAG_HTL1LHuman T-cell leukemia virus 1 (isolate Melanesia mel5 subtype C) (HTLV-1)
GAG_HTL1AHuman T-cell leukemia virus 1 (strain Japan ATK-1 subtype A) (HTLV-1)
GAG_HTL1MHuman T-cell leukemia virus 1 (strain Japan MT-2 subtype A) (HTLV-1)

HTLV-1 basic zipper factor (HBZ)

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HBZ_HTL1CHuman T-cell leukemia virus 1 (isolate Caribbea HS-35 subtype A) (HTLV-1) reference strain
HBZ_HTL1LHuman T-cell leukemia virus 1 (isolate Melanesia mel5 subtype C) (HTLV-1)
HBZ_HTL1AHuman T-cell leukemia virus 1 (strain Japan ATK-1 subtype A) (HTLV-1)

Accessory protein p12I

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P12I_HTL1CHuman T-cell leukemia virus 1 (isolate Caribbea HS-35 subtype A) (HTLV-1) reference strain
P12I_HTL1AHuman T-cell leukemia virus 1 (strain Japan ATK-1 subtype A) (HTLV-1)

Accessory protein p30II

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P30II_HTL1CHuman T-cell leukemia virus 1 (isolate Caribbea HS-35 subtype A) (HTLV-1) reference strain
P30II_HTL1AHuman T-cell leukemia virus 1 (strain Japan ATK-1 subtype A) (HTLV-1)

Gag-Pro-Pol polyprotein (Pr160Gag-Pro-Pol)

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POL_HTL1CHuman T-cell leukemia virus 1 (isolate Caribbea HS-35 subtype A) (HTLV-1) reference strain
POL_HTL1LHuman T-cell leukemia virus 1 (isolate Melanesia mel5 subtype C) (HTLV-1)
POL_HTL1AHuman T-cell leukemia virus 1 (strain Japan ATK-1 subtype A) (HTLV-1)

Gag-Pro polyprotein (Pr76Gag-Pro)

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PRO_HTL1CHuman T-cell leukemia virus 1 (isolate Caribbea HS-35 subtype A) (HTLV-1) reference strain
PRO_HTL1LHuman T-cell leukemia virus 1 (isolate Melanesia mel5 subtype C) (HTLV-1)
PRO_HTL1AHuman T-cell leukemia virus 1 (strain Japan ATK-1 subtype A) (HTLV-1)

Protein Rex (Rev homolog) (Rex-1) (p27Rex)

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REX_HTL1CHuman T-cell leukemia virus 1 (isolate Caribbea HS-35 subtype A) (HTLV-1) reference strain
REX_HTL1LHuman T-cell leukemia virus 1 (isolate Melanesia mel5 subtype C) (HTLV-1)
REX_HTL1FHuman T-cell leukemia virus 1 (isolate Zaire EL subtype B) (HTLV-1)
REX_HTL1AHuman T-cell leukemia virus 1 (strain Japan ATK-1 subtype A) (HTLV-1)

Protein Tax-1 (Protein X-LOR) (Protein PX) (Trans-activating transcriptional regulatory protein of HTLV-1)

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TAX_HTL1CHuman T-cell leukemia virus 1 (isolate Caribbea HS-35 subtype A) (HTLV-1) reference strain
TAX_HTL1LHuman T-cell leukemia virus 1 (isolate Melanesia mel5 subtype C) (HTLV-1)

Protein Tax-1 (Protein X-LOR) (Trans-activating transcriptional regulatory protein of HTLV-1)

TAX_HTL1FHuman T-cell leukemia virus 1 (isolate Zaire EL subtype B) (HTLV-1)

Protein Tax-1 (Protein X-LOR) (Trans-activating transcriptional regulatory protein of HTLV-1)

TAX_HTL1AHuman T-cell leukemia virus 1 (strain Japan ATK-1 subtype A) (HTLV-1)