Related Experiment Videos
Identification of a determinant within the human immunodeficiency virus 1 surface envelope glycoprotein critical for
P Westervelt1, H E Gendelman, L Ratner
1Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110.
Insights
Differences in human immunodeficiency virus 1 replication in monocytes were studied. A specific region of the gp120 protein, amino acids 240-333, was found to confer high-level virus replication in primary monocytes.
Area of Science:
- Virology
- Molecular Biology
Background:
- Human immunodeficiency virus 1 (HIV-1) exhibits varied replication efficiency in primary human monocytes.
- Understanding the genetic determinants of HIV-1 tropism is crucial for developing effective therapies.
Purpose of the Study:
- To identify the molecular basis for differential HIV-1 replication in primary human monocytes.
- To pinpoint specific viral genetic elements responsible for monocyte tropism.
Main Methods:
- Construction of recombinant full-length HIV-1 clones through DNA fragment exchange between monocyte-tropic (ADA) and non-tropic (HXB2, NL4-3) isolates.
- Analysis of viral replication capacity in primary human monocyte cultures.
Main Results:
- Recombinant viruses with ADA vpu or envelope glycoprotein (gp120) N/C termini did not replicate in monocytes.
- A 283-base-pair region of ADA gp120 (amino acids 240-333) conferred high-level replication in primary monocytes.
- This gp120 region, including the third variable domain, showed key amino acid differences compared to non-tropic clones.
Conclusions:
- Specific amino acid residues within the gp120 V3 loop are critical for conferring HIV-1 replication in primary human monocytes.
- The identified residues provide potential targets for therapeutic intervention to control HIV-1 infection.
Abstract:
Profound differences exist in the replicative capacities of various human immunodeficiency virus 1 isolates in primary human monocytes. To investigate the molecular basis for these differences, recombinant full-length clones were constructed by reciprocal DNA fragment exchange between a molecular clone derived from a monocyte-tropic isolate (ADA) and portions of two full-length clones incapable of infection or replication in primary monocyte cultures (HXB2 and NL4-3). Virions derived from proviral clones that contained ADA sequences encoding vpu and the N and C termini of the surface envelope glycoprotein (gp120) were incapable of replication in monocytes. However, a 283-base-pair ADA sequence encoding amino acids 240-333 of the mature gp120 protein conferred the capacity for high-level virus replication in primary monocytes. The predicted amino acid sequence of this ADA clone differed from NL4-3 and HXB2 at 22 of 94 residues in this portion of gp120, which includes the entire third variable domain. Only 2 of 11 residues implicated in CD4 binding are located in this region of gp120 and are identical in HXB2, NL4-3, and ADA. Alignment of the ADA sequence with published amino acid sequences of three additional monocyte-replicative and three monocyte-nonreplicative clones indicates 6 discrete residues with potential involvement in conferring productive human immunodeficiency virus 1 infection of primary monocytes.