DOI: 10.5061/dryad.qbzkh18v9
title: Data from: Primary envelopment of Kaposi’s sarcoma-associated herpesvirus at the nucleoplasmic reticulum

description: Herpesvirus egress begins with primary envelopment of newly assembled
 capsids at the inner nuclear membrane (INM). Primary envelopment has been
 observed at the peripheral INM as well as nuclear infoldings. Nuclear
 infoldings from invaginations of the INM are Type-I nucleoplasmic
 reticulum (NR), whereas infoldings of both INM and outer nuclear membrane
 (ONM) are Type-II NR. Here, we report that Kaposi’s sarcoma-associated
 herpesvirus (KSHV) reactivation from latency and lytic cycle progression
 correlates with increases in both types of NR, but primary envelopment is
 restricted to peripheral INM and Type-I NR. These Type-I NR structures
 co-localized with puncta containing CTP:phosphocholine
 cytidylyltransferase (CCTα), the enzyme that catalyzes the rate-limiting
 step in phosphatidylcholine (PtdCho) synthesis that drives the de novo
 membrane biogenesis and membrane curvature required for NR expansion; CCTα
 recruitment may provide sufficient Type-I NR to facilitate nuclear egress.
 Despite the concurrent expansion of Type-II NR, primary envelopment
 involves a mechanism that specifically targets capsids to Type-I NR.
 Building upon our observation of capsids lacking envelopes in complex
 higher-order Type-I NR structures, we used polar lipid dyes, CLICK-labeled
 fluorescent viral genomes, and fluorescent KSHV capsids to track the fate
 of NR-associated capsids via live cell microscopy. These studies provide
 evidence for trafficking of NR-associated capsids toward the nuclear
 periphery and cytoplasm. Taken together, these findings suggest that
 nuclear egress occurs not only at the nuclear periphery but also at the
 Type-I NR.
description: # Data from: Primary envelopment of Kaposi’s sarcoma-associated
 herpesvirus at the nucleoplasmic reticulum *Journal of Virology*, 2025
 Supplementary material for the manuscript has been uploaded as a single
 file, consisting of dozens of TEM images used to support the datasets
 shown in the main text of the manuscript. Dataset DOI:
 [10.5061/dryad.qbzkh18v9](10.5061/dryad.qbzkh18v9)
 File name: Supp_figure_final.pdf ## Description of the data and file
 structure **Figure S1**. Additional images of nuclear infold events.
 Images correspond to experiments shown in Figs. 3, 4, 5, 6, 8 and 9A.
 Doxycycline-inducible iSLK-BAC16 cells were reactivated with 1 mg/mL
 doxycycline and 1 mM sodium butyrate and harvested 24h, 48h, 72h, 96h or
 120h post-reactivation and processed for transmission electron microscopy.
 (A) Nuclear infolds are indicated by white arrows. In 48h samples, three
 images show the same cell at different magnifications. A yellow box
 matches the higher magnification image provided in figure (A of the main
 text, and pink and green boxes highlight the higher magnification images
 outlined in green and pink elsewhere in the supp. figure. White arrows
 point to Type-I NR events. Convoluted membrane events are grouped and
 labeled as such on the right-hand side. (B) iSLK cells as described in (A)
 demonstrate Type-II NR accumulate over the course of lytic replication.
 Green arrows indicate Type-I NR and blue arrows indicate the Type-II NR.
 ### Files and variables A single .pdf file is attached, with (A) and (B)
 on separate pages. ## Code/software Mac users can open the file in
 preview. Any generic software used to view a .pdf file should be suitable.
 ## Access information Other publicly accessible locations of the data: *
 *Journal of Virology*, 2025. Data was derived from the following sources:
 * N/A