Icerudivirus
Genome
Genome
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[thumb\|upright\=1\.5\|Genome organization of Stygiolobus rod\-shaped virus (SRV), Sulfolopbus islandicus rod\-shaped virus 1 (SIRV1\) and Acidianus rod\-shaped virus 1 (ARV1\)](/wiki/File:F29-02-9780123846846-Rudiviridae-Genomes.png "F29-02-9780123846846-Rudiviridae-Genomes.png")
The genome is composed of linear dsDNA and ranges from 24 kb (ARV1\) to 35 kb (SIRV2\). The two strands of the linear genomes are covalently linked and, at both ends of the genome, there are inverted terminal repeats. The *[Sulfolobus](/wiki/Sulfolobus "Sulfolobus")* rudiviruses size up to 32\.3 kbp for SIRV1 and 35\.8 kbp for SIRV2, with inverted terminal repeats of 2029 bp at the ends of the linear genome. The [G\+C content](/wiki/GC-content "GC-content") of both genomes is extremely low, of only 25%, whereas the genome of *[Sulfolobus solfataricus](/wiki/Sulfolobus_solfataricus "Sulfolobus solfataricus")* (the sequenced genome closest to the virus host) hits 37%.

Although the sequences of the inverted terminal repeats of the rudiviruses are different, they all carry the motif AATTTAGGAATTTAGGAATTT near the genome ends, which may constitute a signal for the [Holliday junction](/wiki/Holliday_junction "Holliday junction") resolvase and [DNA replication](/wiki/DNA_replication "DNA replication").


Are there any other viruses with such low G+C content?