HIV-1 Gag co-localizes with euchromatin histone marks at the nuclear periphery

Area of Science:

• Virology
• Molecular Biology
• Cell Biology

Background:

• The traditional model suggests retrovirus assembly occurs in the cytoplasm or at the plasma membrane.
• Previous research indicated HIV-1 Gag enters the nucleus and binds USvRNA at transcription sites.

Purpose of the Study:

• To investigate the nuclear localization of HIV-1 Gag and its association with USvRNA.
• To explore the hypothesis that gRNA packaging may initiate in the nucleus.

Main Methods:

• Observing HIV-1 Gag trafficking and co-localization with USvRNA in expressing cells.
• Analyzing Gag localization in infected T cells (J-Lat 10.6) and a HeLa cell line with an inducible HIV-1 construct.
• Assessing Gag association with euchromatin histone marks near the nuclear periphery.

Main Results:

• HIV-1 Gag was observed to traffic to the nucleus and co-localize with USvRNA within 8 hours of expression.
• Gag preferentially localized with euchromatin histone marks at enhancer and promoter regions near the nuclear periphery.
• These regions are known favored sites for HIV-1 integration.

Conclusions:

• HIV-1 Gag associates with euchromatin-associated histones to localize to active transcription sites.
• This nuclear localization facilitates the capture of newly synthesized gRNA for packaging.
• The findings support a revised model of HIV-1 assembly initiating in the nucleus.