Figure 1 Negative contrast electron micrographs of virions of representatives of four genera of the family Lipothrixviridae. (Top, left) Thermoproteus tenax virus 1 from the genus Alphalipothrixvirus; (center; left) Sulfolobus islandicus filamentous virus from the genus Betalipothrixvirus; (top, right) Acidianus filamentous virus 1 from the genus Gammalipothrixvirus; (bottom) Acidianus filamentous virus 2 from the genus Deltalipothrixvirus. The bars represent 100 nm.
(Modified from Arnold et al., 2000; Bettstetter et al., 2003, Häring et al., 2005; Vestergaard et al. 2008.)
Figure 2 Negative contrast electron micrograph of intact and partially deteriorated virions of Thermoproteus tenax virus 1, exhibiting the envelope and the core. The bar represents 100 nm.
Figure 3 (Top) Negative contrast electron micrograph of AFV3 virion. The bar represents 100 nm. (Middle row) Image processing of AFV3 virion: (left) average 2D map computed from a set of the negatively stained sample, and (right) average 2D map computed from a set of images taken from cryo-EM micrographs; the contrast is inverted. The bars represent 5 nm. (Bottom) Schematic model of the virion of the Acidianus filamentous virus 3.
Figure 4 Genome maps aligned for the betalipothrixviruses, showing the relative size, location and orientation of the predicted genes. Homologous genes are coded with identical colors. Homologous operons carrying three or more genes are displayed as a consecutive set of genes with the same color. White boxes indicate that no homologous genes were detected in the other genomes. The ORFs of AFV-3 are labelled according to their amino acid lengths. Predicted protein functions are shown as follows: hc, helicase; gt, glycosyltransferase; mt, SAM-dependent methyltransferase; nc, nuclease; pp, protein phosphatase; sp, structural protein; and tr, transcriptional regulator.
Figure 5 Schematic model of the virion of the Acidianus filamentous virus 1.
Figure 6 Topological model of the virion of Acidianus filamentous virus 1, indicating location of the two major structural proteins, P132 and P140. The P132 patch is represented by the blue surface in the center. The dsDNA backbone is orange and the P140 is represented by the grey surface. P140 contacts both the lipid-containing outer shell (in green) and the genomic DNA.
(From Goulet et al., 2009.)
Figure 7 Genome map of Acidianus filamentous virus 1, showing relative size, location, and orientations of the predicted genes. ORFs with significant sequence similarities to ORFs in other viruses are shaded and labeled.
(From Bettstetter et al., 2003.)
Figure 8 Schematic model of the virion of the Acidianus filamentous virus 2.
Figure 9 Genome map of Acidianus filamentous virus 2, showing relative size and location of the predicted genes. Genes are expressed from left to right in the upper row and from right to left in the lower row. ORFs shared with the beta- and gammalipothrixviruses, and with the rudiviruses, are represented by filled rectangles.
Figure 10 Dendrogram for genera Betalipothrixvirus, Gammalipothrixvirus, and Deltalipothrixvirus, derived from comparison of sequences of the only well-conserved putative gene shared by all members of the genera.
(Modified from Vestergaard et al., 2008.)