Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.09.15.298190v1?rss=1 Authors: Knoener, R., Evans, E., Becker, J. T., Scalf, M., Benner, B., Sherer, N. M., Smith, L. M. Abstract: HIV-1 generates unspliced (US), partially spliced (PS), and completely spliced (CS) RNAs; each playing distinct roles in viral replication. Elucidating their host protein "interactomes" is crucial to understanding virus-host interplay. Here, we present HyPR-MSSV for isolation of US, PS, and CS transcripts from a single population of infected CD4+ T-cells and mass spectrometric identification of their in vivo protein interactomes. Analysis revealed 212 proteins differentially associated with the unique RNA classes; including, preferential association of regulators of RNA stability with US- and PS-transcripts and, unexpectedly, mitochondria-linked proteins with US-transcripts. Remarkably, >80 of these factors screened by siRNA knock-down impacted HIV-1 gene expression. Fluorescence microscopy confirmed several to co-localize with HIV-1 US RNA and exhibit changes in abundance and/or localization over the course of infection. This study validates HyPR-MSSV for discovery of viral splice variant protein interactomes and provides an unprecedented resource of factors and pathways likely important to HIV-1 replication. Copy rights belong to original authors. Visit the link for more info