Isolation and characterization of a virus from the intracellular green alga symbiotic with Hydra viridis

Etten, James L. Van; Meints, Russel H.; Burbank, Dwight E.; Kuczmarski, Daniel; Cuppels, Diane A.; Lane, Leslie C.

doi:10.1016/0042-6822(81)90199-9

Cited by 87 publications

(50 citation statements)

References 19 publications

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“…The growth of the host alga, Chlorella strain NC64A, on MBBM medium, plaque assay, production of the viruses, and isolation of virus DNAs have been described (Van Etten et al 1981, 1983a.…”

Section: Viruses and Host Strainsmentioning

confidence: 99%

Intron Conservation in a UV-Specific DNA Repair Gene Encoded by Chlorella Viruses

Sun

Liu²,

McCullough

et al. 2000

J Mol Evol

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Abstract. Large dsDNA-containing chlorella viruses encode a pyrimidine dimer-specific glycosylase (PDG) that initiates repair of UV-induced pyrimidine dimers. The PDG enzyme is a homologue of the bacteriophage T4-encoded endonuclease V. The pdg gene was cloned and sequenced from 42 chlorella viruses isolated over a 12-year period from diverse geographic regions. Surprisingly, the pdg gene from 15 of these 42 viruses contain a 98-nucleotide intron that is 100% conserved among the viruses and another 4 viruses contain an 81-nucleotide intron, in the same position, that is nearly 100% identical (one virus differed by one base). In contrast, the nucleotides in the pdg coding regions (exons) from the introncontaining viruses are 84 to 100% identical. The introns in the pdg gene have 5Ј-AG/GTATGT and 3Ј-TTGCAG/ AA splice site sequences which are characteristic of nuclear-located, spliceosomal processed pre-mRNA introns. The 100% identity of the 98-nucleotide intron sequence in the 15 viruses and the near-perfect identity of an 81-nucleotide intron sequence in another 4 viruses imply strong selective pressure to maintain the DNA sequence of the intron when it is in the pdg gene. However, the ability of intron-plus and intron-minus viruses to repair UV-damaged DNA in the dark was nearly identical. These findings contradict the widely accepted dogma that intron sequences are more variable than exon sequences.

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“…The growth of the host alga, Chlorella strain NC64A, on MBBM medium, plaque assay, production of the viruses, and isolation of virus DNAs have been described (Van Etten et al 1981, 1983a.…”

Section: Viruses and Host Strainsmentioning

confidence: 99%

Intron Conservation in a UV-Specific DNA Repair Gene Encoded by Chlorella Viruses

Sun

Liu²,

McCullough

et al. 2000

J Mol Evol

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“…Cloning and Expression of Recombinant GMD and GMER-Production of virus PBCV-1 and DNA isolation were performed as described (16,17). Gene-specific primers were used for PCR amplification of the * This work was supported by the Italian Consiglio Nazionale delle Ricerche (CNR) Target Project "Biotechnology," CNR Agenzia 2000, CNR/Ministry for Education, University, and Research Project (Legge 95/95) "Biomolecole per la salute umana" and Grant GM-32441 from the National Institutes of General Medical Sciences (to J. V. E.).…”

Section: Methodsmentioning

confidence: 99%

Paramecium bursaria Chlorella Virus 1 Encodes Two Enzymes Involved in the Biosynthesis of GDP-L-fucose and GDP-D-rhamnose

Tonetti¹,

Zanardi²,

Gurnon

et al. 2003

Journal of Biological Chemistry

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At least three structural proteins in Paramecium bursaria Chlorella virus (PBCV-1) are glycosylated, including the major capsid protein Vp54. However, unlike other glycoprotein-containing viruses that use host-encoded enzymes in the endoplasmic reticulum-Golgi to glycosylate their proteins, PBCV-1 encodes at least many, if not all, of the glycosyltransferases used to glycosylate its structural proteins. As described here, PBCV-1 also encodes two open reading frames that resemble bacterial and mammalian enzymes involved in de novo GDP-L-fucose biosynthesis. This pathway, starting from GDP-D-mannose, consists of two sequential steps catalyzed by GDP-D-mannose 4,6 dehydratase (GMD) and GDP-4-keto-6-deoxy-D-mannose epimerase/ reductase, respectively. The two PBCV-1-encoded genes were expressed in Escherichia coli, and the recombinant proteins had the predicted enzyme activity. However, in addition to the dehydratase activity, PBCV-1 GMD also had a reductase activity, producing GDP-D-rhamnose. In vivo studies established that PBCV-1 GMD and GDP-4-keto-6-deoxy-D-mannose epimerase/reductase are expressed after virus infection and that both GDP-L-fucose and GDP-D-rhamnose are produced in virus-infected cells. Thus, PBCV-1 is the first virus known to encode enzymes involved in nucleotide sugar metabolism. Because fucose and rhamnose are components of the glycans attached to Vp54, the pathway could circumvent a limited supply of GDP sugars by the algal host. Paramecium bursaria Chlorella virus (PBCV-1)1 is the prototypical member of a group of large polyhedral, plaque-forming viruses in the family Phycodnaviridae that replicate in certain unicellular, eukaryotic Chlorella-like green algae (1). The PBCV-1 genome, which has been sequenced, consists of a large (Ͼ330 kb) linear, non-permuted double-stranded DNA with covalently closed hairpin ends (2). Additional features of the virus have been reviewed recently (3). The PBCV-1 major capsid protein, Vp54, located on the viral surface, is one of three glycosylated viral proteins. The glycan portion of Vp54 contains seven neutral sugars, glucose, fucose, rhamnose, galactose, mannose, xylose, and arabinose (4) that contribute to the protease resistance and antigenicity of the virus. Recently, the Vp54 crystal structure was solved, and four N-linked glycosylation sites and two O-linked oligosaccharides were identified (5).

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“…After the isolated algae had been incubated for 24-36 hr in Bold's basal medium, virus was purified by the HVCV-1 procedure (4). Procedures for determining the sedimentation coefficients in sucrose density gradients and buoyant densities in CsCl have been described (4). All of the virions contained a double-stranded DNA genome and isolation of the DNA, its treatment with restriction endonucleases, and electrophoresis of the DNA fragments have been described (4).…”

Section: Methodsmentioning

confidence: 99%

“…We recently found that a large (185 nm in diameter) doublestranded DNA virus (designated began to multiply in the algae shortly after they were isolated from the Florida strain of hydra; replication of the virus resulted in lysis of the entire population of algae within 24 hr (3,4). The appearance of the virus certainly impedes the culturing of this alga.…”

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confidence: 99%

Viruses of symbiotic Chlorella -like algae isolated from Paramecium bursaria and Hydra viridis

Etten

Meints

Kuczmarski

et al. 1982

Proc. Natl. Acad. Sci. U.S.A.

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We previously reported that isolation of symbiotic Chloreila-like algae from the Florida strain ofHydra viridis induced replication of a virus (designated HVCV-1) in the algae. We now report that isolation ofsymbiotic Chlorella-like algae from four other sources of green hydra and one source ofthe protozoan Paramecium bursaria also induced virus synthesis. Algae from one of these hydra contained a virus identical to HVCV-1 (based on its rate of sedimentation, buoyant density, reaction to HVCV-1 antiserum, and DNA restriction fragments) whereas algae from the other three hydra contained. another similar, but distinct, virus (designated HVCV-2). The virus from the paramecium algae (designated PBCV-1) was distinct from both HVCV-1 and HVCV-2. The symbiotic algae in the hydra could also be distinguished ultrastructurally. Chloroplasts of both algae that produced HVCV-1 lacked a pyrenoid whereas chloroplasts of the other three symbiotic algae contained pyrenoids. Since all symbiotic eukaryotic algae we have examined have had virus, a potential viral role in symbiosis is suggested.

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Isolation and characterization of a virus from the intracellular green alga symbiotic with Hydra viridis

Cited by 87 publications

References 19 publications

Intron Conservation in a UV-Specific DNA Repair Gene Encoded by Chlorella Viruses

Intron Conservation in a UV-Specific DNA Repair Gene Encoded by Chlorella Viruses

Paramecium bursaria Chlorella Virus 1 Encodes Two Enzymes Involved in the Biosynthesis of GDP-L-fucose and GDP-D-rhamnose

Viruses of symbiotic Chlorella -like algae isolated from Paramecium bursaria and Hydra viridis

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