AI Summary
The content explains the distinct stabilization mechanism of the human T cell leukemia virus type 1 (HTLV-1) immature Gag lattice, as compared to other retroviruses. Cryo-electron tomography studies revealed that HTLV-1 uses a unique mechanism of Gag-Gag interactions for lattice formation, with the N-terminal domain of the capsid (CA) being the primary stabilizing component. This differs from other retroviruses where stabilization is primarily provided by the C-terminal domain of CA. Understanding the structural details of Gag arrangement in HTLV-1 sheds light on why its particles have a unique morphology. This research has implications for understanding HTLV-1 assembly and could offer insights into potential therapeutic strategies.
Human T cell leukemia virus type 1 (HTLV-1) immature particles differ in morphology from other retroviruses, suggesting a distinct way of assembly. Here we report the results of cryo-electron tomography studies of HTLV-1 virus-like particles assembled in vitro, as well as derived from cells. This work shows that HTLV-1 uses a distinct mechanism of Gag–Gag interactions to form the immature viral lattice. Analysis of high-resolution structural information from immature capsid (CA) tubular arrays reveals that the primary stabilizing component in HTLV-1 is the N-terminal domain of CA. Mutagenesis analysis supports this observation. This distinguishes HTLV-1 from other retroviruses, in which the stabilization is provided primarily by the C-terminal domain of CA. These results provide structural details of the quaternary arrangement of Gag for an immature deltaretrovirus and this helps explain why HTLV-1 particles are morphologically distinct.
The Retroviridae family includes two important human pathogens infecting T cells, human immunodeficiency virus type 1 (HIV-1) and human T cell leukemia virus type 1 (HTLV-1). The global prevalence suggests that the number of people living with HTLV-1 (a member of the Deltaretrovirus genus) ranges from 5 to 10 million, which is likely an underestimate1.