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ID: 548
Plasmavirus L2

Acholeplasma phage L2

Lineage: Viruses[25651]; Plasmaviridae[1]; Plasmavirus[1]; Plasmavirus L2[1]

Description of Plasmaviridae

adapted from ICTVdb

Virion Properties


Virions consist of an envelope, a nucleoprotein complex, and a core, or a capsid. Virus capsid is enveloped. Virions are spherical to pleomorphic; spherical structures that lack cores are common (thin sections show particles with lucent centers, and virions with densely stained centers, seemingly containing condensed DNA). Virions measure (50-)80(-125) nm in diameter with a loose fitting membrane (baggy membrane). A regular capsid structure is not detectable. The core is spherical (and densely stained in thin sections, consists of a nucleoprotein complex. Structure not detectable, but images of thin sections are suggesting an asymmetric nucleoprotein condensation bounded by a lipid-protein membrane. The genome is condensed.

Physicochemical and Physical Properties

Virions are sensitive to treatment with or inactivated by ether, non-ionic detergents (Brij-58, Triton-X, and Nonidet P-40), chloroform, heat. The infectivity is not affected by irradiation (virions can be reactivated after UV irradiation in host cells by excision and SOS DNA repair systems, decreased when deproteinized with proteases.

Nucleic Acid

The genome is not segmented and contains a single molecule of circular, supercoiled, double-stranded DNA. The complete genome is 12000 nucleotides long. The DNA is sequenced, but only an estimate is available, complete sequence is 12000 nucleotides long. The genome has a guanine + cytosine content of 32 %.


The viral genome encodes structural proteins. Virions consist of at least 4 structural protein(s) located in the envelope.


Lipids are present and located in the envelope. The composition of viral lipids and host cell membranes are similar. The lipids are of host origin and are derived from host cell membranes (and variation of host cell fatty acid composition leads to virions with corresponding fatty acid composition variations). Lipids in the viral membrane have a bilayer structure.


Carbohydrates have not been reported.

Genome Organization and Replication

Infection and Replication: Infection involves a noncytocidal productive infectious cycle that is followed by a lysogenic cycle in each infected cell. Prophage DNA must be activated (derepressed) before replication. After initial replication of viral genome the infecting nucleic acid may become latent within the host; complete. Lysogeny involves integration into the host chromosome at a unique site. The host chromosome; due to a repressor, lysogens are resistant to superinfection by homologous virus. Lysogens are not resistant to superinfection by heterologous virus (apparently due to a repressor). Latent infection can be induced by UV-irradiation, or mitomycin C. Transcription: The virus codes for at least 15 ORF(s). The viral genome is transcribed from the viral sense strand. At least 11 viral mRNA(s) is/are transcribed with an overlap; viral mRNA(s) is/are transcribed from at least 8 promoter(s, viral mRNA(s) is/are transcribed in a unidirectional coding arrangement. Release: Infected cells produce prophages. Host cells survive as lysogens. Noncytocidal infection involves progeny virus release. Virus is released from host cell by budding through the cell membrane.


Assembly level: Complete Genome
Assembly: GCA_000837825.1 ViralProj14066 scaffolds: contigs: N50: 11,965 L50: 1
Statistics: total length (Mb): 0.011965
 protein count: 14
 GC%: 32

Replicon Info

Type Name RefSeq INSDC Size (Kb) GC% Protein Gene

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