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At least 19 recordsLinked to original sources
PubMed1992

Sequence and analysis of the capsid protein of Nudaurelia capensis omega virus, an insect virus with T = 4 icosahedral symmetry.

We have determined the nucleotide sequence of the RNA2 segment of the Nudaurelia capensis omega virus genome. It was found to consist of 2448 nucleotides and contained one long open reading frame (ORF) encoding the 644 residue capsid protein. The deduced amino acid sequence of this protein reveals a positively charged amino terminus, a characteristic exhibited by several other viral capsid proteins, that is thought to be important for interactions between the capsid and the genomic RNA. There are 366 and 150 bases of untranslated sequence on the 5' and 3' ends, respectively. The ORF encoding the capsid protein initiates at the second AUG from the 5' end. The 5' proximal AUG specifies a short ORF (30 codons) which terminates 1 base before the initiation codon for the coat protein. Our analysis also revealed the presence of a second, previously unidentified polypeptide associated with Nudaurelia capensis omega virus particles. The amino terminal sequence of this protein corresponds to a portion of the long ORF beginning at codon 571. The lack of an initiation codon near this sequence indicates that the small polypeptide is most likely produced as a carboxy terminal cleavage product from a 70-kDa capsid protein precursor, yielding the previously identified 62-kDa protein and the 8-kDa protein that we have observed. The putative cleavage site would be at an Asn/Phe pair, somewhat resembling known cleavage sites (Asn/Ala) in the T = 3 Nodaviridae. In addition, we have found that there is also a second polypeptide similar in size to that from Nudaurelia capensis omega virus associated with particles of Nudaurelia capensis beta virus, the type member of Tetraviridae.

Amino Acid Sequence↗
PubMed1987

Expression of envelope glycoproteins of human immunodeficiency virus by an insect virus vector.

The envelope gene of human immunodeficiency virus was inserted into the genome of an insect virus vector (Autographa californica nuclear polyhedrosis virus). Upon infection of tissue culture cells, this recombinant virus produced immunoreactive polypeptides related to the envelope glycoproteins of human immunodeficiency virus. Serological survey indicates such polypeptides would be of value as antigens in diagnostics for acquired immunodeficiency syndrome.

Animals↗
PubMed2005

Crystal lattice as biological phenotype for insect viruses.

Many insect viruses survive for long periods by occlusion within robust crystalline polyhedra composed primarily of a single polyhedrin protein. We show that two different virus families form polyhedra which, despite lack of sequence similarity in the virally encoded polyhedrin protein, have identical cell constants and a body-centered cubic lattice. It is almost inconceivable that this could have arisen by chance, suggesting that the crystal lattice has been preserved because it is particularly well-suited to its function of packaging and protecting viruses.

Animals↗
PubMed1983

The process of virus assembly in insect virus mixed infections.

Interference occurred upon infection of the cabbage moth caterpillars (Mamestra brassicae L.) with a mixture of nuclear polyhedrosis virus (NPV) and cytoplasmic polyhedrosis virus (CPV), resulting in the impairment of virus assembly, and formation of abnormal nucleocapsids. At the same time protein supercapsids were produced normally, but contained no infectious virions. When insects were infected with related viruses, the virions developed as usual, but the protein supercapsids revealed abnormal forms.

Animals↗
PubMedDate not supplied

The three-dimensional structure of frozen-hydrated Nudaurelia capensis beta virus, a T = 4 insect virus.

The three-dimensional structure of Nudaurelia capensis beta virus (N beta V) was reconstructed to 3.2-nm resolution from images of frozen-hydrated virions. The distinctly icosahedral capsid (approximately 40-nm diameter) contains 240 copies of a single 61-kDa protein subunit arranged with T = 4 lattice symmetry. The outer surface of unstained virions compares remarkably well with that previously observed in negatively stained specimens. Inspection of the density map, volume estimates, and model building experiments indicate that each subunit consists of two distinct domains. The large domain (approximately 40 kDa) has a cylindrical shape, approximately 4-nm diameter by approximately 4-nm high, and associates with two large domains of neighboring subunits to form a Y-shaped trimeric aggregate in the outer capsid surface. Four trimers make up each of the 20 planar faces of the capsid. Small domains (approximately 21 kDa) presumably associate at lower radii (approximately 13-16.5 nm) to form a contiguous, non-spherical shell. A T = 4 model, constructed from 80 trimers of the common beta-barrel core motif (approximately 20 kDa) found in many of the smaller T = 3 and pseudo T = 3 viruses, fits the dimensions and features seen in the N beta V reconstruction, suggesting that the contiguous shell of N beta V may be formed by intersubunit contacts between small domains having that motif. The small (approximately 1800 kDa), ssRNA genome is loosely packed inside the capsid with a low average density.

Animals↗
PubMed1981

Occurrence of antibodies against insect virus proteins in mammals: simple model to differentiate between passive exposure and active virus growth.

Antibodies against an "enterovirus-like" virus of insects, cricket paralysis virus, occur in the sera of domestic animals. When these antibodies were used in combination with the immunoprecipitation of radiolabeled virus proteins from infected Drosophila cells in culture, it could be demonstrated that the animals were exposed to preformed virus.

Animals↗
PubMed2005

Infection with the insect virus Hz-2v alters mating behavior and pheromone production in female Helicoverpa zea moths.

The effect of Hz-2V virus infection on the reproductive physiology and behavior of infected Helicoverpa zea female moths was examined. In the absence of males, infected females exhibited calling behavior and called as often but for shorter periods on average than control females. As expected, control females mated with males for extend periods when they were present and did not call after mating, while virus-infected females made many frequent contacts with males and continued to call even after these contacts. Virus-infected females were found to produce five to seven times more pheromone than control females and attracted twice as many males as did control females in flight tunnel experiments. The ability of Hz-2V to alter the physiology and behavior of infected females observed here may serve to facilitate the transmission of virus in insect populations.

Animals↗
PubMed1996

Nucleotide sequence, temporal expression, and transcriptional mapping of the p34 late gene of the Hz-1 insect virus.

A late gene of the Hz-1 insect virus (Hz-1V) encoding a predicted polypeptide of 34 kilodaltons (kDa) was isolated from a cDNA library and mapped to the HindIII-T region (50.3 to 52.4 map units) of the viral genome. The p34 gene was characterized by DNA sequence, Northern blot, and primer extension analyses. The 765-bp open reading frame (ORF) is transcribed in the clockwise direction as a 1.2-kb RNA. Primer extension analysis detected two late transcription initiation sites at -16 and -17 nt relative to the start of the p34 ORF. Transcription initiation was observed between 4 and 18 hr postinfection (hr p.i.) with maximum expression at 12 hr p.i. No nucleotide sequence homology was detected between the regulatory region of the p34 gene and the baculovirus conserved late promoter motif NTAAG. This observation was substantiated by results obtained from an investigation of Hz-1V late gene expression using a transient expression assay system which suggested that Hz-1V late gene promoters do not resemble the baculovirus late promoter motif. This is the first molecular analysis of Hz-1V late gene expression and offers a basis by which to compare Hz-1V to other insect viruses.

Amino Acid Sequence↗
PubMed1987

Structure of an insect virus at 3.0 A resolution.

We report the first atomic resolution structure of an insect virus determined by single crystal X-ray diffraction. Black beetle virus has a bipartite RNA genome encapsulated in a single particle. The capsid contains 180 protomers arranged on a T = 3 surface lattice. The quaternary organization of the protomers is similar to that observed in the T = 3 plant virus structures. The protomers consist of a basic, crystallographically disordered amino terminus (64 residues), a beta-barrel as seen in other animal and plant virus subunits, an outer protrusion composed predominantly of beta-sheet and formed by three large insertions between strands of the barrel, and a carboxy terminal domain composed of two distorted helices lying inside the shell. The outer surfaces of quasi-threefold related protomers form trigonal pyramidyl protrusions. A cleavage site, located 44 residues from the carboxy terminus, lies within the central cavity of the protein shell. The structural motif observed in BBV (a shell composed of 180 eight-stranded antiparallel beta-barrels) is common to all nonsatellite spherical viruses whose structures have so far been solved. This highly conserved shell architecture suggests a common origin for the coat protein of spherical viruses, while the primitive genome structure of BBV suggests that this insect virus represents an early stage in the evolution of spherical viruses from cellular genes.

Biological Evolution↗
PubMed1956

The structure of insect virus particles.

THIN SECTIONS HAVE BEEN CUT OF THE VIRUS PARTICLES FROM FOUR TYPES OF INSECT VIRUS DISEASES: cytoplasmic polyhedroses of lepidopterous larvae, a nuclear polyhedrosis of Tipula paludosa (Diptera), a granulosis from Melanchra persicariae (Lepidoptera), and a new virus disease without polyhedra from T. paludosa. The cytoplasmic polyhedral viruses are thought to have composite particles in some cases. The shape and enveloping membranes of the different virus particles are compared. In the new virus disease of T. paludosa some of the virus particles appear to be empty; inclusion bodies surrounded by complicated membranes are also demonstrated.

Animals↗