Disease relevance of AMV187

• Identification, cloning, and sequencing of a fragment of Amsacta moorei entomopoxvirus DNA containing the spheroidin gene and three vaccinia virus-related open reading frames [1].
• Primer extension experiments also showed that spheroidin gene transcripts contain 5' poly(A) sequences typical of vertebrate poxvirus late transcripts [1].
• Entomopoxvirus virions are frequently contained within crystalline occlusion bodies, which are composed of primarily a single protein, spheroidin, which is analogous to the polyhedrin protein of baculovirus [1].
• A series of AmEPV-lacZ recombinants was constructed in which the lacZ gene was regulated by either late (the AmEPV spheroidin or the cowpox virus A-type inclusion [ATI]) or early (the AmEPV esp [early strong promoter; derived from a 42-kDa AmEPV protein] or the Melolontha melolontha EPV fusolin, fus) virus promoters [2].
• Assembly of Amsacta moorei entomopoxvirus spheroidin into spheroids following synthesis in insect cells using a baculovirus vector [3].

High impact information on AMV187

• When the AmEPV recombinants were used to infect vertebrate cells, beta-galactosidase expression occurred (in >30% of the cells) when lacZ was regulated by either the fus or esp early promoters but not when lacZ was regulated by the late promoters (spheroidin or ATI) [2].
• An analysis of open reading frames around the spheroidin gene suggests that the colinear core of "essential genes" typical of the vertebrate poxviruses is absent in A. moorei entomopoxvirus [1].
• The spheroidin gene of Amsacta moorei entomopoxvirus was identified following the microsequencing of polypeptides generated from cyanogen bromide treatment of spheroidin and the subsequent synthesis of oligonucleotide hybridization probes [1].
• Three copies of the heptanucleotide, TTTTTNT, a sequence associated with early gene transcription in the vertebrate poxviruses, and four in-frame translational termination signals were found within 60 bp upstream of the putative spheroidin gene promoter (TAAATG) [1].
• These results imply that downstream coding sequences within the SPH gene enhance SPH gene expression only within the insect environment [4].

Biological context of AMV187

• The spheroidin gene promoter region contains the sequence TAAATG, which is found in many late promoters of the vertebrate poxviruses and which serves as the site of transcriptional initiation, as shown by primer extension [1].
• The predicted amino acid sequence of the spheroidin protein from Amsacta moorei entomopoxvirus: lack of homology between major occlusion body proteins of different poxviruses [5].
• However, when a cassette containing the spheroidin gene and putative promoter was inserted into cowpox (CPV) or vaccinia viruses, only very low levels of spheroldin gene expression were observed [6].
• A transfer vector, pAmCP1, was prepared containing a unique BamHI site in lieu of the spheroidin gene coding region, together with 1 kbp of upstream and downstream DNA sequence that flanks the spheroidin gene [7].
• We also show this newly identified Choristoneura homolog of the AmEPV spheroidin gene as well as the AmEPV spheroidin gene itself are both located at the 3' end of an NPH I gene and are highly homologous in all three viruses, indicating that this region of the genome in the three viruses is co-linear [8].

Associations of AMV187 with chemical compounds

• AaEPV spheroidin contains 21 cysteine residues (2.2%) and 14 N-glycosylation putative sites distributed along the sequence [9].

Analytical, diagnostic and therapeutic context of AMV187

• These results were confirmed by immunofluoresence microscopy and Western blotting using a specific antipeptide antibody to spheroidin, and suggest that the supramolecular assembly of spheroids is not dependent on other EPV-encoded gene products [3].
• Light microscopy and SDS-PAGE analysis demonstrated that no spheroids or spheroidin protein were produced in the recombinant virus-infected cells [7].
• The spheroidin gene was located in the AaEPV genome by Southern blot and hybridisation with specific degenerated oligonucleotides probes synthesised after partial sequencing of the purified spheroidin protein [9].

References