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K Strebel

Publications and source records attributed to K Strebel.

42 records · Page 3Linked to original sources
PubMed1986

Characterization of foot-and-mouth disease virus gene products with antisera against bacterially synthesized fusion proteins.

Defined segments of the cloned foot-and-mouth disease virus genome corresponding to all parts of the coding region were expressed in Escherichia coli as fusions to the N-terminal part of the MS2-polymerase gene under the control of the inducible lambda PL promoter. All constructs yielded large amounts of proteins, which were purified and used to raise sequence-specific antisera in rabbits. These antisera were used to identify the corresponding viral gene products in 35S-labeled extracts from foot-and-mouth disease virus gene products in the nucleotide sequence, to identify precursor-product relationships, and to detect several foot-and-mouth disease virus gene products not previously identified in vivo or in vitro.

Animals↗
PubMed1986

A second protease of foot-and-mouth disease virus.

Foot-and-mouth disease virus (FMDV) genes are expressed as a polyprotein which is rapidly processed into the four primary cleavage products L, P1, P2, and P3. In secondary cleavage reactions, these are further processed into the mature proteins. The FMDV L protein is located at the N terminus of the polyprotein and is the first gene product released from the nascent polyprotein. For analysis of its biological function, the L gene was mutated by site-directed mutagenesis of cloned cDNA. In vitro translation of in vitro transcripts of these DNAs and expression studies in Escherichia coli showed that the L mutants affect the processing of the viral polyprotein. The mutants isolated were partially or totally defective in processing the polyprotein at the L/P1 junction. These mutants could, however, be processed in the presence of the wild-type L protein. Furthermore, an antiserum directed against the L protein inhibited processing at the L/P1 cleavage site, so that the release of the L protein from the polyprotein was blocked. These data reveal that the L gene product represents a viral protease which catalyzes its own release from the nascent polyprotein.

Animals↗
PubMed1984

Nucleotide sequence and genome organization of foot-and-mouth disease virus.

A continuous 7802 nucleotide sequence spanning the 94% of foot and mouth disease virus RNA between the 5'-proximal poly(C) tract and the 3'-terminal poly(A) was obtained from cloned cDNA, and the total size of the RNA genome was corrected to 8450 nucleotides. A long open reading frame was identified within this sequence starting about 1300 bases from the 5' end of the RNA genome and extending to a termination codon 92 bases from its polyadenylated 3' end. The protein sequence of 2332 amino acids deduced from this coding sequence was correlated with the 260 K FMDV polyprotein. Its processing sites and twelve mature viral proteins were inferred from protein data, available for some proteins, a predicted cleavage specificity of an FMDV encoded protease for Glu/Gly(Thr, Ser) linkages, and homologies to related proteins from poliovirus. In addition, a short unlinked reading frame of 92 codons has been identified by sequence homology to the polyprotein initiation signal and by in vitro translation studies.

Amino Acid Sequence↗
PubMed1983

Structure of the FMDV translation initiation site and of the structural proteins.

A cDNA clone of Foot and Mouth Diseases Virus (FMDV), strain C1, has been sequenced. The limits of the structural genes were defined by comparison with the available protein data. We identified two potential translation initiation sites for the viral polyprotein separated by 84 nucleotides. We suggest that these two initiation sites could be used to express two proteins differing only at the N-terminal, P16 and P20a. This model is supported by the fact that antiserum against a bacterially synthesized polypeptide corresponding to the anterior region of the polyprotein precipitates specifically both P16 and P20a. Comparison of the C1 sequence with two other serotypes, O1K and A10 revealed variability in the major immunogenic structural protein, VP1, and also in two other capsid proteins, VP2 and VP3. P16/P20a, VP4, and the N-terminal part of the precursor of the nonstructural genes, P52, are rather conserved between the different FMDV strains.

Aphthovirus↗
PubMedDate not supplied

The HIV 'A' (sor) gene product is essential for virus infectivity.

The genome of the human immunodeficiency virus (HIV) contains several open reading frames (ORFs) not present in other viruses. The 'A' gene, also known as Q2 P'3, ORF-1(4) or sor5, partially overlaps the pol gene; its protein product has a relative molecular mass of 23,000 (Mr 23K) and is present in productively infected cells. The function of this protein is unclear; mutant viruses deleted in 'A' replicate in and kill CD4+ lymphocyte lines, but the high degree of conservation of the deduced amino-acid sequence in nine different HIV isolates (80%) and the presence of analogous genes in HIV-2 and other lentiviruses suggest that the gene function is an important one. Here we describe a mutant virus deficient in the 'A' gene which produces virion particles normally; however, the particles are approximately 1,000 times less infective than wild type. Transcomplementation experiments partially restore infectivity. The mutant virus spreads efficiently when virus-producing cells are co-cultivated with CD4+ lymphocytes, however, indicating that HIV can spread from cell to cell in a mechanism that does not require the 'A' gene product and probably does not require the production of infective virus particles.

Amino Acid Sequence↗