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Characterization of intracellular reverse transcription complexes of human immunodeficiency virus type 1

A Fassati1, S P Goff

  • 1Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA.

Journal of Virology
|March 27, 2001
PubMed

Insights

Early human immunodeficiency virus type 1 (HIV-1) life cycle events show that only one type of reverse transcription complex (RTC) synthesizes DNA. Key proteins dissociate, but Vpr remains, and RTCs remain competent for reverse transcription for hours post-infection.

Area of Science:

  • Virology
  • Molecular Biology
  • Cellular Biology

Background:

  • Understanding the early stages of human immunodeficiency virus type 1 (HIV-1) infection is crucial for developing effective antiviral strategies.
  • Intracellular reverse transcription complexes (RTCs) are key players in the HIV-1 life cycle, mediating the conversion of viral RNA into DNA.

Purpose of the Study:

  • To investigate the composition and function of early intracellular RTCs during HIV-1 infection.
  • To identify the viral and cellular components involved in early reverse transcription.

Main Methods:

  • Analysis of intracellular RTCs isolated from acutely HIV-1 infected cells.
  • Partial purification of RTCs using equilibrium density fractionation and velocity sedimentation.
  • Assessment of reverse transcription activity and protein association within RTCs at different time points post-infection.

Main Results:

  • Two species of RTCs were identified, but only one was capable of DNA synthesis.
  • Most capsid, matrix, and reverse transcriptase (RT) proteins dissociated early, while Vpr remained associated with RTCs.
  • RTCs isolated 1, 4, and 7 hours post-infection remained competent for in vitro reverse transcription, indicating persistent RT association.
  • Early RTCs exhibited a sedimentation velocity of approximately 560S, with later species ranging from 350S to 100S, and nuclear-associated RTCs at 80S.
  • Viral strong-stop DNA within RTCs transitioned from nuclease sensitivity to protection as reverse transcription neared completion.

Conclusions:

  • HIV-1 RTCs undergo significant structural changes and protein dissociation early in infection.
  • Despite protein loss, RTCs maintain reverse transcription competence for several hours.
  • The association of Vpr and the dynamic nature of RTCs highlight their complex role in early viral replication.

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