13.7 - 24.1 kb
||Archaeal virus Fuselloviridae spp.
||Krupovic M, Prangishvili D, Hendrix RW, Bamford DH. Genomics of bacterial and archaeal viruses: dynamics within the prokaryotic virosphere. Microbiol Mol Biol Rev. 2011 Dec75(4):610-35. doi: 10.1128/MMBR.00011-11 p.623 right column top paragraphPubMed ID22126996
|| Held NL, Whitaker RJ. Viral biogeography revealed by signatures in Sulfolobus islandicus genomes. Environ Microbiol. 2009 Feb11(2):457-66. doi: 10.1111/j.1462-2920.2008.01784.x  Muskhelishvili G, Palm P, Zillig W. SSV1-encoded site-specific recombination system in Sulfolobus shibatae. Mol Gen Genet. 1993 Mar237(3):334-42PubMed ID19196276, 8483447
||Primary source  abstract: "The biogeographic distribution of viruses that infect Sulfolobus islandicus is investigated using genome comparisons among four newly identified, integrated, Sulfolobus spindle-shaped viruses and previously sequenced viral strains…In addition, signatures of host-virus interactions recorded in the sequence-specific CRISPR (clustered regularly interspaced short palindromic repeats) system show that hosts have interacted with viral communities that are more closely related to local viral strains than to foreign ones." Primary source  abstract: "[Investigators] present evidence for the existence of a conservative site-specific recombination system in Archaea by demonstrating integrative recombination of Sulfolobus shibatae virus SSV1 DNA with the host chromosome, catalysed by the SSV1-encoded integrase in vitro."
||P.623 left column bottom paragraph: "Fuselloviruses possess lemon- or spindle-shaped virions with short filamentous appendages at one pointed end (Fig. 6) and infect hyperthermophilic hosts from the crenarchaeal genera Sulfolobus and Acidianus (refs 213, 231). In addition to a spindle-like morphology, virions of fuselloviruses can display a pleomorphic appearance, as was found to be the case for the viruses Sulfolobus spindle-shaped virus 6 (SSV6) and Acidianus spindle-shaped virus 1 (ASV1) (morphology ranging from thin-cigar- to pear-like) (Fig. 6) (ref 231). The circular dsDNA genomes of fuselloviruses (13.7 to 24.1 kb) are positively supercoiled and have been shown to integrate site specifically into the host chromosome (primary sources)."