Unconventional stabilization of the human T-cell leukemia virus type 1 immature Gag lattice.
Obr, M., Percipalle, M., Chernikova, D., Yang, H., Thader, A., Pinke, G., Porley, D., Mansky, L.M., Dick, R.A., Schur, F.K.(2023) bioRxiv 
- PubMed: 37546793 
- DOI: https://doi.org/10.1101/2023.07.24.548988
- Primary Citation of Related Structures:  
8PU6, 8PU7, 8PU8, 8PU9, 8PUA, 8PUB, 8PUC, 8PUD, 8PUE, 8PUF, 8PUG, 8PUH - PubMed Abstract: 
Human T-cell leukemia virus type 1 (HTLV-1) has an atypical immature particle morphology compared to other retroviruses. This indicates that these particles are formed in a way that is unique. Here we report the results of cryo-electron tomography (cryo-ET) studies of HTLV-1 virus-like particles (VLPs) assembled in vitro , as well as derived from cells. This work shows that HTLV-1 employs an unconventional mechanism of Gag-Gag interactions to form the immature viral lattice. Analysis of high-resolution structural information from immature CA tubular arrays reveals that the primary stabilizing component in HTLV-1 is CA-NTD. Mutagenesis and biophysical analysis support this observation. This distinguishes HTLV-1 from other retroviruses, in which the stabilization is provided primarily by the CA-CTD. These results are the first to provide structural details of the quaternary arrangement of Gag for an immature deltaretrovirus, and this helps explain why HTLV-1 particles are morphologically distinct.
Organizational Affiliation: 
Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria.