Figure 1 (Top left) Cryo-image reconstructions of the two morphologies represented within the family Microviridae: (left) Spiroplasma phage 4 (SpV4) (genus Spiromicrovirus); (right) Enterobacteria phage φX174 (φX174) (genus Microvirus) (courtesy T. Baker, R. McKenna and M.G. Rossmann). (Top right) Negative contrast electron micrograph of φX174 particles. The bar represents 50 nm. (Bottom) Electronic rendering surface of φX174 particles (left, scaffold; center, procapsid) and diagram representing the T=1 lattice.
(Dokland et al. (1997). Nature, 389, 308–313)
Figure 2 Genome organization of members of the family Microviridae. The circular genomes are presented linearly. Due to pronounced protein homologies and genome arrangements, the same gene number scheme is used for both the bdellomicroviruses (Bdellovibrio phage φMH2K; φMH2K) and chlamydiamicroviruses (Chlamydia phage 2; Chp2). Four proteins in Spiroplasma phage 4 (SpV4), (the products of genes 1, 2, 4, and 8) have homologs in the chlamydia- and bdellomicroviruses, the number in parentheses indicates the homologous gene.
Figure 3 Microvirus capsid morphogenesis.
Figure 4 (opposite) Phylogeny of the family Microviridae. The aa sequences of the capsid protein (tTop left), the Rep protein (top right), the DNA pilot protein (bottom left) and the internal scaffolding protein (bottom right) were used to make alignments with the CLUSTAL X software. The trees were designed with PAUP and the bootstrap values are indicated above 50%. The abbreviations of the viruses used and their GenBank accession numbers are listed in the List of Species of the description.