Cafeteria roenbergensis virus

[4] Among its 544 predicted protein-coding genes are several that are usually restricted to cellular organisms, such as translation factors and enzymes for DNA repair and carbohydrate synthesis.

The virus packages several distinct groups of proteins, including a presumably complete base excision repair (BER) pathway.

[8] Mature CroV consists of a 300 nm diameter outer protein shell with icosahedral symmetry, an underlying lipid membrane, and an inner core that contains the genome.

[citation needed] CroV is the sole member of the genus Cafeteriavirus in the family Mimiviridae within the proposed order Megavirales.

Acanthamoeba polyphaga mimivirus is its closest known relative, although the two viruses share less than one-third of homologous genes.

Due to production of transcriptional genes, like that of tRNA synthetase, the virus is able to modify and regulate host translational machinery that results in CroV being less dependent on host-cell components.

The presence and expression of 10 genes involved in glycoprotein synthesis were identified, suggesting that CroV is able to potentially partake in virion-cell recognition.

It encodes an entire biosynthetic pathway for the creation of 3-Deoxy-D-manno-oct-2-ulosonic acid, or KDO, which is a component of the cell walls of gram-negative bacteria.

When there are low numbers of Cafeteria roenbergensis due to extensive CroV infections, the bacterial populations rise exponentially.

Cryo-EM images of CroV compared to APMV. (A) Cryo-electron micrograph of four CroV particles. (B) Single CroV particle with concave core depression (white arrow). (C) Single APMV particle. Scale bars in (A–C) represent 2,000 Å.
Cryo-EM reconstruction of the CroV virion and capsomer arrangements of other giant icosahedral viruses. (A) Reconstruction of the CroV capsid. The isosurface of the map was colored by pentasymmetrons (purple) and trisymmetrons (blue, red, green, cyan and orange). One of the 30 edges of the icosahedron is marked by a cyan line. Two surface areas (a,b) are magnified and selected capsomers are labeled by yellow triangles to show their orientations. (B–E) Isolated icosahedral faces of CroV, PBCV-1, CIV and PpV01 capsids are shown schematically. Their T-numbers, asymmetric unit capsomer numbers, and trisymmetron capsomer numbers are listed. 5-fold, 3-fold, and 2-fold symbols are indicated in red and ASUs are outlined in blue.
A diagram of CroV's genome, showing the functional categories of what the genome encodes for, when in the viral life the genes are expressed, the types of promoters, as well as the types of repeats.
VF is the “virus factory,” where replication of CroV occurs. The white arrowhead indicates newly formed CroV particles. The white long-stem arrows indicate mavirus, a virophage that infects CroV.