Primate T-lymphotropic virus 1

Molecular biology


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


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.


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.



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.


Global map HTLV-I virus infection source

Matching UniProtKB/Swiss-Prot entries

31 entries grouped by strain (browse by keywords)

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

9 entries

Human T-cell leukemia virus 1 (isolate Caribbea HS-35 subtype A) (HTLV-1) reference strain

Select_all Deselect_all  
ENV_HTL1CEnvelope glycoprotein gp62 (Env polyprotein)
GAG_HTL1CGag polyprotein (Pr53Gag)
HBZ_HTL1CHTLV-1 basic zipper factor (HBZ)
P12I_HTL1CAccessory protein p12I
P30II_HTL1CAccessory protein p30II
POL_HTL1CGag-Pro-Pol polyprotein (Pr160Gag-Pro-Pol)
PRO_HTL1CGag-Pro polyprotein (Pr76Gag-Pro)
REX_HTL1CProtein Rex (Rev homolog) (Rex-1) (p27Rex)
TAX_HTL1CProtein Tax-1 (Protein X-LOR) (Protein PX) (Trans-activating transcriptional ...

9 entries

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

Select_all Deselect_all  
ENV_HTL1AEnvelope glycoprotein gp62 (Env polyprotein)
GAG_HTL1AGag polyprotein (Pr53Gag)
HBZ_HTL1AHTLV-1 basic zipper factor (HBZ)
P12I_HTL1AAccessory protein p12I
P30II_HTL1AAccessory protein p30II
POL_HTL1AGag-Pro-Pol polyprotein (Pr160Gag-Pro-Pol)
PRO_HTL1AGag-Pro polyprotein (Pr76Gag-Pro)
REX_HTL1AProtein Rex (Rev homolog) (Rex-1) (p27Rex)
TAX_HTL1AProtein Tax-1 (Protein X-LOR) (Protein PX) (Trans-activating transcriptional ...

7 entries

Human T-cell leukemia virus 1 (isolate Melanesia mel5 subtype C) (HTLV-1)

Select_all Deselect_all  
ENV_HTL1LEnvelope glycoprotein gp62 (Env polyprotein)
GAG_HTL1LGag polyprotein (Pr53Gag)
HBZ_HTL1LHTLV-1 basic zipper factor (HBZ)
POL_HTL1LGag-Pro-Pol polyprotein (Pr160Gag-Pro-Pol)
PRO_HTL1LGag-Pro polyprotein (Pr76Gag-Pro)
REX_HTL1LProtein Rex (Rev homolog) (Rex-1) (p27Rex)
TAX_HTL1LProtein Tax-1 (Protein X-LOR) (Trans-activating transcriptional regulatory ...

3 entries

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

Select_all Deselect_all  
ENV_HTL1FEnvelope glycoprotein gp62 (Env polyprotein)
REX_HTL1FProtein Rex (Rev homolog) (Rex-1) (p27Rex)
TAX_HTL1FProtein Tax-1 (Protein X-LOR) (Trans-activating transcriptional regulatory ...

2 entries

Human T-cell leukemia virus 1 (strain Japan MT-2 subtype A) (HTLV-1)

Select_all Deselect_all  
ENV_HTL1MEnvelope glycoprotein gp62 (Env polyprotein)
GAG_HTL1MGag polyprotein (Pr53Gag)

1 entry

Human T-cell leukemia virus 1 (isolate Caribbea CH subtype A) (HTLV-1)

ENV_HTL1NEnvelope glycoprotein gp62 (Env polyprotein)