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. 2010 Sep 30;6(9):e1001127. doi: 10.1371/journal.ppat.1001127

Figure 1. Biological properties of DI-T particles.

Figure 1

(A) Structure of VSV and DI-T genomic RNAs. The single-stranded negative-sense RNA genomes are shown in a 3′-5′ orientation. The five viral genes are colored as follows: red nucleocapsid (N) protein gene; orange, phosphoprotein (P) gene; yellow, matrix (M) protein gene; green, glycoprotein (G) gene; blue, large (L) polymerase protein gene. The noncoding genomic terminal leader (Le) and trailer (Tr) regions, which serve as promoters for RNA synthesis and genomic RNA encapsidation, are shown in gray. The DI-T genome comprises 2,208 nts. The 5′ terminal 2,163 nts derive from the 5′ terminus of the parental VSV genome (11,161 nts), and the 3′terminus contains a 45 nt inverted complement of the wild-type Tr (TrC). (B) Electron micrographs of purified VSV and DI-T particles negatively stained with PTA. Middle panel, inset shows an expanded view of virions from the boxed region to facilitate visualization of the viral glycoprotein spikes. Inset scale bar, 100 nm. (C) Virion geometry. The dimensions of individual DI-T (blue) and VSV (red) particles measured from electron micrographs of negatively stained particles. Each open circle represents the measurement for a single particle. Horizontal red lines denote the mean value of each population, and the numerical means (+/− SD) are provided above each plot. (D) Protein composition of purified VSV and DI-T particles. Viral proteins (L, G, P, N, and M) were separated by SDS-PAGE and visualized with Coomassie blue staining. The ratio of N protein to G protein was quantified using ImageJ and is displayed below the gel as a comparative measure of average virion surface glycoprotein density in each particle population. (E) Fluorescence intensity of virus particles labeled with Alexa Fluor dye molecules. Purified DI-T or VSV particles were labeled with Alexa Fluor 647 or 568 and imaged on separate glass coverslips using a spinning disk confocal microscope. The fluorescence intensity of individual spots in a single field of view was quantified, and the distribution of intensity values (in arbitrary units, a.u.) for DI-T (blue) and VSV (red) particles is shown.