Previous Article | Next Article ![]()
Journal of Virology, November 1998, p. 8697-8704, Vol. 72, No. 11
Institut für Virologie (FB
Veterinärmedizin), Justus-Liebig-Universität, D-35392
Giessen, Germany
Received 22 May 1998/Accepted 24 July 1998
Molecular characterization of cytopathogenic (cp) bovine viral
diarrhea virus (BVDV) strain CP Rit, a temperature-sensitive strain
widely used for vaccination, revealed that the viral genomic RNA is
about 15.2 kb long, which is about 2.9 kb longer than the one of
noncytopathogenic (noncp) BVDV strains. Molecular cloning and
nucleotide sequencing of parts of the genome resulted in the identification of a duplication of the genomic region encoding nonstructural proteins NS3, NS4A, and part of NS4B. In addition, a
nonviral sequence was found directly upstream of the second copy of the
NS3 gene. The 3' part of this inserted sequence encodes an N-terminally
truncated ubiquitin monomer. This is remarkable since all described cp
BVDV strains with ubiquitin coding sequences contain at least one
complete ubiquitin monomer. The 5' region of the nonviral sequence did
not show any homology to cellular sequences identified thus far in cp
BVDV strains. Databank searches revealed that this second cellular
insertion encodes part of ribosomal protein S27a. Further analyses
included molecular cloning and nucleotide sequencing of the cellular
recombination partner. Sequence comparisons strongly suggest that the
S27a and the ubiquitin coding sequences found in the genome of CP Rit
were both derived from a bovine mRNA encoding a hybrid protein with the
structure NH2-ubiquitin-S27a-COOH. Polyprotein processing
in the genomic region encoding the N-terminal part of NS4B, the two
cellular insertions, and NS3 was studied by a transient-expression
assay. The respective analyses showed that the S27a-derived
polypeptide, together with the truncated ubiquitin, served as
processing signal to yield NS3, whereas the truncated ubiquitin alone
was not capable of mediating the cleavage. Since the expression of NS3
is strictly correlated with the cp phenotype of BVDV, the altered
genome organization leading to expression of NS3 most probably
represents the genetic basis of cytopathogenicity of CP Rit.
0022-538X/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Ribosomal S27a Coding Sequences Upstream of
Ubiquitin Coding Sequences in the Genome of a Pestivirus
*
Corresponding author. Mailing address: Institut
für Virologie (FB Veterinärmedizin),
Justus-Liebig-Universität Giessen, Frankfurter Str. 107, D-35392
Giessen, Germany. Phone: 49 641 99 38350. Fax: 49 641 99 38359. E-mail:
heinz-juergen.thiel{at}vetmed.uni-giessen.de.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»