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S C Inglis

Publications and source records attributed to S C Inglis.

At least 37 records · Page 2Linked to original sources
PubMed1990

Identification of a new membrane-associated polypeptide specified by the coronavirus infectious bronchitis virus.

Nucleotide sequences from the third open reading frame of mRNA D (D3) of infectious bronchitis virus (IBV) were expressed in bacteria as part of a fusion protein with beta-galactosidase. Antiserum raised in rabbits against this fusion protein immunoprecipitated from IBV-infected chick kidney or Vero cells a polypeptide of 12.4K, the size expected for a D3-encoded product. The D3 polypeptide is apparently non-glycosylated, and appears to be associated with the membrane fraction of infected cells, as judged by cell fractionation and immunofluorescence.

Amino Acid Sequence↗
PubMed1989

Characterization of an efficient coronavirus ribosomal frameshifting signal: requirement for an RNA pseudoknot.

The genomic RNA of the coronavirus IBV contains an efficient ribosomal frameshifting signal at the junction of two overlapping open reading frames. We have defined by deletion analysis an 86 nucleotide sequence encompassing the overlap region which is sufficient to allow frameshifting in a heterologous context. The upstream boundary of the signal consists of the sequence UUUAAAC, which is the likely site of ribosomal slippage. We show by creation of complementary nucleotide changes that the RNA downstream of this "slippery" sequence folds into a tertiary structure termed a pseudoknot, the formation of which is essential for efficient frameshifting.

Base Composition↗
PubMed1989

Complex formation between influenza virus polymerase proteins expressed in Xenopus oocytes.

All three influenza virus polymerase (P) proteins were expressed in Xenopus oocytes from microinjected in vitro transcribed mRNA analogs, with yields of up to 100 ng per oocyte. To examine the functional state of the Xenopus-expressed P proteins, the polypeptides were tested for their ability to form stable complexes with each other. As seen in virus-infected cells, all three P proteins associated into an immunoprecipitable complex, suggesting that the system has considerable promise for the reconstruction of an active influenza RNA polymerase. Examination of the ability of paired combinations of the P proteins to associate indicated that PB1 contained independent binding sites for PB2 and PA, and so probably formed the backbone of the complex. Sedimentation analysis of free and complexed P proteins indicated that PB1 and PB2 did not exist as free monomers, and that similarly, complexes of all three P proteins did not simply consist of one copy of each protein. The heterodisperse sedimentation rate seen for complexes of all three P proteins did not appear to result from their binding to RNA, suggesting the incorporation of additional polypeptides in the polymerase complex.

Animals↗
PubMed1987

An efficient ribosomal frame-shifting signal in the polymerase-encoding region of the coronavirus IBV.

The polymerase-encoding region of the genomic RNA of the coronavirus infectious bronchitis virus (IBV) contains two very large, briefly overlapping open reading frames (ORF), F1 and F2, and it has been suggested on the basis of sequence analysis that expression of the downstream ORF, F2, might be mediated through ribosomal frame-shifting. To examine this possibility a cDNA fragment containing the F1/F2 overlap region was cloned within a marker gene and placed under the control of the bacteriophage SP6 promoter in a recombinant plasmid. Messenger RNA transcribed from this plasmid, when translated in cell-free systems, specified the synthesis of polypeptides whose size was entirely consistent with the products predicted by an efficient ribosomal frame-shifting event within the overlap region. The nature of the products was confirmed by their reactivity with antisera raised against defined portions of the flanking marker gene. This is the first non-retroviral example of ribosomal frame-shifting in higher eukaryotes.

Amino Acid Sequence↗
PubMed1985

Regulated production of an influenza virus spliced mRNA mediated by virus-specific products.

The influenza virus NS2 mRNA is generated through processing by cellular enzymes of a transcript (the NS1 mRNA) of virion RNA segment 8. Production of this mRNA is altered in cells infected with a mutant of influenza A (fowl plague) virus. The proportion of segment 8 transcripts which accumulated in a spliced form was found to be considerably lower in mutant virus-infected cells than in cells infected with wild-type virus, and the amplification in production of NS2 mRNA relative to that of the NS1 mRNA, which normally occurs during infection with wild-type virus, was not observed with the mutant. The NS1 mRNA specified by the mutant virus has unaltered splice recognition sites and was apparently processed normally during a mixed infection with a strain of virus which is wild-type for production of NS2 mRNA. These results suggest that the production of NS2 mRNA is regulated by virus-specific products; these products may act by increasing the efficiency of splicing of NS1 mRNA.

Animals↗
PubMed1984

Differences in the control of virus mRNA splicing during permissive or abortive infection with influenza A (fowl plague) virus.

Spliced transcripts of influenza A (fowl plague) virus (FPV) RNA (vRNA) segments 7 and 8 accumulate to a much greater extent during non-productive infection of mouse L cells, than they do during productive infection in primary chick embryo fibroblasts (CEF). Virus-specific protein synthesis, or a consequent event in virus replication appears necessary to promote splicing of vRNA segment 8-encoded mRNAs in both cell types, and of vRNA segment 7-encoded mRNAs in CEF. In L cells, however, splicing of the segment 7-encoded mRNAs seems to be independent of such virus-specific control. This observation is discussed in relation to the defect in expression of vRNA 7 which has been observed previously in FPV-infected L cells, and which is thought to account for the failure of virus replication.

Animals↗
PubMed1983

Sequence analysis of fowl plague virus mutant ts47 reveals a nonsense mutation in the NS1 gene.

A mutant of fowl plague virus, ts47, induces the synthesis in infected cells of a truncated NS1 polypeptide at both permissive and restrictive temperatures. Nucleotide sequence analysis of the segment coding for the NS1 polypeptide, segment 8, indicates that this aberration is due to a nonsense mutation. This mutation occurs in the region of the NS1 gene which overlaps with the NS2 gene and there is a corresponding amino acid substitution in the NS2 polypeptide. While it is not clear which polypeptide is responsible for the thermal instability of ts47, the loss of the COOH-terminal 28 amino acid residues from the NS1 polypeptide does not affect replication of the virus at permissive temperatures.

Base Sequence↗
PubMed1982

Nucleotide sequence of fowl plague virus RNA segment 7.

Nucleotide sequence analysis of a recombinant DNA clone of RNA segment 7 from FPV/Rostock/34 has shown it to be highly conserved in comparison with RNA segment 7 from two human strains (Allen et al., 1980; Winter & Fields, 1980; Lamb & Lai, 1981). FPV RNA segment 7 contains the coding capacity for two polypeptide chains. The sequence homology between RNA segment 7 of avian and human viruses was greater than 90%, and most of the changes did not result in amino acid substitutions.

Base Sequence↗
PubMed1982

Inhibition of host protein synthesis and degradation of cellular mRNAs during infection by influenza and herpes simplex virus.

Cloned DNA copies of two cellular genes were used to monitor, by blot hybridization, the stability of particular cell mRNAs after infection by influenza virus and herpesvirus. The results indicated that the inhibition of host cell protein synthesis that accompanied infection by each virus could be explained by a reduction in the amounts of cellular mRNAs in the cytoplasm, and they suggested that this decrease was due to virus-mediated mRNA degradation.

Actins↗
PubMed1981

Spliced and unspliced RNAs encoded by virion RNA segment 7 of influenza virus.

Cells infected with the avian influenza virus fowl plague virus, contains three species of polyadenylated RNA which are complementary to virion RNA segment 7. The largest is virtually a complete transcript of vRNA 7, and is the messenger RNA for the matrix protein, but the coding function of the two smaller species, which are approximately 320 and 285 nucleotides long (excluding poly(A)), is unknown. It is likely however that at least one of the small RNAs encodes a new virus polypeptide which has been predicted from the nucleotides sequence of vRNA 7. The major part of each RNA maps within about 300 nucleotides from the 5'-terminus of vRNA 7, but the larger species also contains additional sequences derived from the 3' terminus. Production of the two small RNAs may involve alternative patterns of splicing of the matrix protein mRNA.

Animals↗
PubMed1980

Relationship between the messenger RNAs transcribed from two overlapping genes of influenza virus.

The relationship of the mRNAs encoding the NS1 and NS2 polypeptides of influenza virus has been investigated through synthesis and characterisation of complementary DNA copies of the mRNAs. Previous work had shown that both mRNAs are encoded by virion RNA segment 8, and that the sequences comprising the smaller of the two mRNAs (the NS2 mRNA) were also present on the NS1 mRNA. Our results indicate that the mRNA encoding the NS2 polypeptide of the avian influenza, fowl plague virus, is approximately 400 ntds long, and that its sequences correspond largely with the 3'-terminal region of the NS1 mRNA.

DNA, Viral↗
PubMed1980

An influenza virus gene encoding two different proteins.

Evidence is presented which confirms that the influenza virus genome specifies a polypeptide of molecular mass 11 000, in addition to the eight previously recognized gene products. A summary is included of results that show that this polypeptide is encoded by the smallest genome segment of the virus (segment 8) which also encodes a polypeptide of molecular mass 23 000 (NS1). The implications of these findings are considered.

Animals↗
PubMed1979

The smallest genome RNA segment of influenza virus contains two genes that may overlap.

The genome of influenza virus consists of eight segments of single-stranded RNA, each of which encodes a different polypeptide. In addition to the eight recognized gene products, the virus specifies a distinct smaller nonstructural polypeptide (NS2), which is translated from a separate species of virus-specific mRNA. The location on the virus genome of the gene encoding this polypeptide was investigated by hybridization of the NS2 mRNA with isolated subgenomic RNA species, and by correlation of the inheritance of a strain-specific NS2 with inheritance of particular genome RNA segments during recombination between two different virus strains. The genetic information for NS2 was found to reside in the smallest genome RNA segment of the virion, which also encodes the NS1 polypeptide. Considering the sizes of the molecules involved, it is likely that the coding sequences for the two polypeptides overlap.

Genes, Viral↗