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29. Iridoviridae

29.3. Lymphocystivirus

Virion Genome Replication Strategy History Genus Members Nucleotide Sequences Proteins Biology Diseases Vaccine Strains Vector Constructs Key References

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29. Iridoviridae

29.3. Lymphocystivirus Contributed by   Christian A. Tidona and Gholamreza Darai Fig. 1: Lymphocystis disease virus 1 (ultrathin section of intracellular mature virion, bar = 100 nm)

Virion

Morphology:  icosahedral Envelope:  no Diameter:  215-240 nm Structural components:  core, capsid Buoyant density:  unknown Additional information:  capsid contains internal lipid layer

Genome

Nucleic acid:  DNA Strandedness:  double-stranded Configuration:  linear Segments:  non-segmented Size:  102.7 kbp G+C content:  29.1 % Transcription units:  90-110 Additional information:  genome is circularly permuted and terminally redundant; viral DNA is highly methylated at cytosines in CpG dinucleotides

Fig. 2: Genome organization of Lymphocystis disease virus 1

Replication Strategy

Entry mechanism:  unknown Site of transcription:  unknown Transcriptase:  virus-encoded DNA-dependent RNA polymerase Site of genome replication:  cytoplasm Replicase:  virus-encoded DNA-dependent DNA polymerase Replication intermediate:  unknown Site of virion assembly:  cytoplasm, virogenic stroma Egress mechanism:  rupture of lymphocystis giant cells Additional information:  high accumulation of virus progeny in cytoplasm of lymphocystis cells

History

Year Event Reference 1874 First description of lymphocystis disease in teleost fish Lowe K (1874) IV. Trans Norfolk and Norwich Nat Soc Fishes, pp 21-56 1962 Identification of lymphocystis virus in lesions of infected fish (pike perch) by electron microscopy Walker R (1962) Virology 18:503-505 1966 Isolation of lymphocystis virus from bluegill and propagation in centrarchid fish cell lines Wolf K, et al. (1966) Science 151:1004-1005 1974 Experimental transmission of lymphocystis disease from flounder and plaice to healthy animals Russell PH (1974) J Fish Biol 6:771-778 1983 Characterization of the genome structure of LCDV-1 (from flounder) and LCDV-2 (from dab) Darai G, et al. (1983) Virology 126:466-479 1997 Determination of the complete DNA sequence of LCDV-1 Tidona CA, Darai G (1997) Virology 230:207-216

Genus Members

Species name Abbreviation Synonymous species name Wild-type strains Host range Membership status Lymphocystis disease virus 1 LCDV-1 fish lymphocystis disease virus (FLDV-f) 4/82 flounder, plaice type species Lymphocystis disease virus 2 LCDV-2 fish lymphocystis disease virus (FLDV-d)   dab tentative member

Nucleotide Sequences

Genomic region Virus species Strain Nucleotides Accession number Reference complete genome LCDV-1 4/82 102653 L63545 Tidona CA, Darai G (1997) Virology 230:207-216

Proteins

Protein name Abbreviations MW (kDa) Time of expression Accession numbers Additional information cytosine-specific DNA-methyltransferase 005L 27.0 unknown AAB50571   DNA-dependent RNA polymerase, subunit A 016L 134.4 unknown AAA92868   DNA-dependent RNA polymerase, subunit B 025L 116.7 unknown L63545   ribonucleotide reductase, small subunit 027R 44.2 unknown L63545   cathepsin B-like cysteine proteinase 043R 49.1 unknown L63545   putative DNA packaging ATPase 054R 28.1 unknown L63545   31 kDa protein homolog of Frog virus 3 122R 27.6 unknown L63545   insulin-like growth factor homolog 125R 8.8 unknown L63545 signal peptide DNA-dependent DNA polymerase 135R 108.3 unknown L63545   thymidine kinase 136R 22.3 unknown L63545   putative ribonuclease 137R 28.9 unknown L63545   major capsid protein 147L, MCP 51.3 late KIXFFV   3-beta-hydroxysteroid dehydrogenase 153L 39.1 unknown L63545 leucine zipper tumor necrosis factor receptor homolog 167L 29.1 unknown L63545, AAC25600 no transmembrane domain ribonucleotide reductase, large subunit 176L 61.6 unknown L63545

Biology

Virus species Permissive cell lines Tissue tropism Cytopathic effects Additional information LCDV-1 unknown peripheral fibroblasts and osteoblasts formation of hypertrophic lymphocystis giant cells

Diseases

Disease name Causative agent Affected organisms Disease characteristics Route of transmission Geographic distribution lymphocystis disease all genus members teleost fish clusters of grey nodules on fins and skin unknown world-wide

Vaccine Strains

Not available

Vector Constructs

Not available

Key References

[1] Flügel RM (1985) Curr Top Microbiol Immunol 116:133-150 [2] Schnitzler P, Rösen-Wolff A, Darai G (1990) In: Darai G (ed) Molecular Biology of Iridoviruses. Kluwer Academic Publishers, Boston Dordrecht London, pp 203-234 [3] Tidona CA, Schnitzler P, Kehm R, Darai G (1998) Virus Genes 16:59-66

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© 1999-2001 by Christian A. Tidona