PubMed Health⌕ Search

Biomedical subjects

A V Totmenin

Publications and source records attributed to A V Totmenin.

At least 19 recordsLinked to original sources
PubMed2002

Analysis of the monkeypox virus genome.

Monkeypox virus (MPV) belongs to the orthopoxvirus genus of the family Poxviridae, is endemic in parts of Africa, and causes a human disease that resembles smallpox. The 196,858-bp MPV genome was analyzed with regard to structural features and open reading frames. Each end of the genome contains an identical but oppositely oriented 6379-bp terminal inverted repetition, which similar to that of other orthopoxviruses, includes a putative telomere resolution sequence and short tandem repeats. Computer-assisted analysis was used to identify 190 open reading frames containing >/=60 amino acid residues. Of these, four were present within the inverted terminal repetition. MPV contained the known essential orthopoxvirus genes but only a subset of the putative immunomodulatory and host range genes. Sequence comparisons confirmed the assignment of MPV as a distinct species of orthopoxvirus that is not a direct ancestor or a direct descendent of variola virus, the causative agent of smallpox.

Animals↗
PubMed2001

Human monkeypox and smallpox viruses: genomic comparison.

Monkeypox virus (MPV) causes a human disease which resembles smallpox but with a lower person-to-person transmission rate. To determine the genetic relationship between the orthopoxviruses causing these two diseases, we sequenced the 197-kb genome of MPV isolated from a patient during a large human monkeypox outbreak in Zaire in 1996. The nucleotide sequence within the central region of the MPV genome, which encodes essential enzymes and structural proteins, was 96.3% identical with that of variola (smallpox) virus (VAR). In contrast, there were considerable differences between MPV and VAR in the regions encoding virulence and host-range factors near the ends of the genome. Our data indicate that MPV is not the direct ancestor of VAR and is unlikely to naturally acquire all properties of VAR.

Amino Acid Sequence↗
PubMed2000

Alastrim smallpox variola minor virus genome DNA sequences.

Alastrim variola minor virus, which causes mild smallpox, was first recognized in Florida and South America in the late 19th century. Genome linear double-stranded DNA sequences (186,986 bp) of the alastrim virus Garcia-1966, a laboratory reference strain from an outbreak associated with 0.8% case fatalities in Brazil in 1966, were determined except for a 530-bp fragment of hairpin-loop sequences at each terminus. The DNA sequences (EMBL Accession No. Y16780) showed 206 potential open reading frames for proteins containing >/=60 amino acids. The amino acid sequences of the putative proteins were compared with those reported for vaccinia virus strain Copenhagen and the Asian variola major strains India-1967 and Bangladesh-1975. About one-third of the alastrim viral proteins were 100% identical to correlates in the variola major strains and the remainder were >/=95% identical. Compared with variola major virus DNA, alastrim virus DNA has additional segments of 898 and 627 bp, respectively, within the left and right terminal regions. The former segment aligns well with sequences in other orthopoxviruses, particularly cowpox and vaccinia viruses, and the latter is apparently alastrim-specific.

3-Hydroxysteroid Dehydrogenases↗
PubMed2000

Conserved surface-exposed K/R-X-K/R motifs and net positive charge on poxvirus complement control proteins serve as putative heparin binding sites and contribute to inhibition of molecular interactions with human endothelial cells: a novel mechanism for evasion of host defense.

Vaccinia virus complement control protein (VCP) has been shown to possess the ability to inhibit both classical and alternative complement pathway activation. The newly found ability of this protein to bind to heparin has been shown in previous studies to result in uptake by mast cells, possibly promoting tissue persistence. It has also been shown to reduce chemotactic migration of leukocytes by blocking chemokine binding. In addition, this study shows that VCP-through its ability to bind to glycosaminoglycans (heparin-like molecules) on the surface of human endothelial cells-is able to block antibody binding to surface major histocompatibility complex class I molecules. Since heparin binding is critical for many functions of this protein, we have attempted to characterize the molecular basis for this interaction. Segments of this protein, generated by genetic engineering of the DNA encoding VCP into the Pichia pastoris expression system, were used to localize the regions with heparin binding activity. These regions were then analyzed to more specifically define their properties for binding. It was found that the number of putative binding sites (K/R-X-K/R), the overall positive charge, and the percentage of positively charged amino acids within the protein were responsible for this interaction.

Amino Acid Motifs↗
PubMed1998

The genomic sequence analysis of the left and right species-specific terminal region of a cowpox virus strain reveals unique sequences and a cluster of intact ORFs for immunomodulatory and host range proteins.

Sequencing and computer analysis of the left (52,283 bp) and right (49,649 bp) variable DNA regions of the cowpox virus strain GRI-90 (CPV-GRI) has revealed 51 and 37 potential open reading frames (ORFs), respectively. Comparison of the structure-function organization of these DNA regions of CPV-GRI with those previously published for corresponding regions of genomes of vaccinia virus, strains Copenhagen (VAC-COP) and Western Reserve (VAC-WR); and variola major virus, strains India-1967 (VAR-IND), Bangladesh-1975 (VAR-BSH); and alastrim variola minor virus, strain Garcia-1966 (VAR-GAR), was performed. Within the left terminal region under study, an extended DNA sequence (14,171 bp), unique to CPV, has been found. Within the right region of the CPV-GRI genome two segments, which are unique to CPV DNA (1579 and 3585 bp) have been found. Numerous differences have been revealed in the genetic structure of CPV-GRI DNA regions, homologous to fragments of the genomes of the above-mentioned orthopoxvirus strains. A cluster of ORFs with structural similarity ot immunomodulatory and host range function of other poxviruses have also been detected. A comparison of the sequences of ORF B, crmA, crmB, crmC, IMP, and CHO hr genes of CPV Brighton strain (CPV-BRI) with the corresponding genes in strain GRI-90 have revealed an identity at the amino acid level ranging from 82 to 96% between the two strains. The findings are significant in light of the recent demonstration of CPV as an important poxvirus model system to probe the precise in vivo role(s) of the unique virally encoded immunomodulatory proteins. Also, the presence of a complete and intact repertoire of immunomodulatory proteins, ring canal proteins family, and host range genes indicates that CPV may have been the most ancient of all studied orthopoxviruses.

Amino Acid Sequence↗
PubMed1998

Molecular mimicry of the inflammation modulatory proteins (IMPs) of poxviruses: evasion of the inflammatory response to preserve viral habitat.

Microorganisms encode numerous immunomodulators that resemble, in structure and function, molecules captured over the millennia from their hosts [G. J. Kotwal J. Leukoc. Biol. 62, 415-429]. The vaccinia virus complement control protein (VCP) was the first soluble microbial protein to have a postulated role in the immunomodulation and evasion of host defense [G. J. Kotwal and B. Moss Nature 355, 176-179]. Purified bioactive VCP has been shown to bind to C3 and C4, block the complement cascade at multiple sites [G. J. Kotwal et al. Science 250, 827-830; R. Mckenzie, G. J. Kotwal et al. J. Infect. Dis. 166, 1245-1250] and exhibit a greater potency than the human complement 4b binding protein, C4b-BP [G. J. Kotwal, Am. Biotech. Lab. 9, 76]. The importance of this protein to poxviruses was further demonstrated in rabbits and guinea pigs through the use of recombinant virus lacking an intact DNA coding for VCP [Isaacs, G. J. Kotwal, and B. Moss Proc. Natl. Acad. Sci. 89, 628-672]. Studies in mice have shown that the homolog of VCP in cowpox virus (CPV), referred to as the inflammation modulatory protein (IMP) can, in a mouse model, significantly diminish the specific footpad swelling response [C. G. Miller, S. N. Shchelkunov, and G. J. Kotwal Virol. 229, 126-133]. To determine the precise cellular changes at the site of infection, BALB/c mice were subcutaneously injected (in the backs) with CPV or a recombinant virus lacking IMP, CPV-IMP. Differences in histology were observed by staining the adjoining skin tissue sections with hematoxylin & eosin or by removal of the connective tissue and staining with May-Grunwald-Geimsa. All mice that were injected with the CPV-IMP experienced severe tissue destruction and formation of nodular lesions compared with the mice injected with CPV. Microscopic examination indicated significantly greater cellular infiltration and destruction of skeletal muscle cells in the sections of connective tissue and adjoining skin tissue, respectively, of the mice injected with the CPV-IMP [G. J. Kotwal et al. Mol. Cell. Biochem. in press]. Thus IMP preserves the tissue at the site of infection (viral habitat). In this review, we present evidence for molecular mimicry and evolutionary relationship to other homologs of IMP and discuss their relationships with other IMPs such as the poxviral chemokine and cytokine receptor-like proteins.

Amino Acid Sequence↗
PubMed1996

Terminal region sequence variations in variola virus DNA.

Genome DNA terminal region sequences were determined for a Brazilian alastrim variola minor virus strain Garcia-1966 that was associated with an 0.8% case-fatality rate and African smallpox strains Congo-1970 and Somalia-1977 associated with variola major (9.6%) and minor (0.4%) mortality rates, respectively. A base sequence identity of > or = 98.8% was determined after aligning 30 kb of the left- or right-end region sequences with cognate sequences previously determined for Asian variola major strains India-1967 (31% death rate) and Bangladesh-1975 (18.5% death rate). The deduced amino acid sequences of putative proteins of > or = 65 amino acids also showed relatively high identity, although the Asian and African viruses were clearly more related to each other than to alastrim virus. Alastrim virus contained only 10 of 70 proteins that were 100% identical to homologs in Asian strains, and 7 alastrim-specific proteins were noted.

Africa↗
PubMed1996

Analysis of the nucleotide sequence of 23.8 kbp from the left terminus of the genome of variola major virus strain India-1967.

Sequencing and computer analysis of the nucleotide sequence of variola major virus strain India-1967 (VAR-IND) DNA segment (23 786 bp) covering the left variable region of the viral genome has been carried out. Twenty-nine potential open reading frames were identified. Structure-function organization of the VAR-IND DNA segment was compared with previously reported sequences from analogous genome regions of vaccinia virus strains Copenhagen (VAC-COP) and Western Reserve (VAC-WR). Multiple structural differences between the VAR-IND and genome regions were analysed and both VAC-COP and VAC-WR have been found. Possible molecular factors of virulence, virus host range genes as well as differences revealed in the structure of these genes of VAR and VAC will be discussed.

Amino Acid Sequence↗
PubMed1995

Two types of deletions in orthopoxvirus genomes.

The genome nucleotide sequences of two strains of variola major virus and one strain of vaccinia virus were compared. One hundred and sixty-eight short (less than 100 bp in length) and eight long (more than 900 bp in length) deletions, four deletion/insertion regions, and four regions of multiple mutational differences between variola and vaccinia virus DNAs were revealed. Short deletions generally occur at directly repeated sequences of 3-21 bp. Long deletions showed no evidence of repeated sequences at their points of junction. We suggest the presence of a consensus sequence characteristic of these junctions and propose that there is a virus-encoded enzyme that produces this nonhomologous recombination/deletion in the cytoplasm of the infected cell.

Base Sequence↗
PubMed1994

Analysis of the nucleotide sequence of 48 kbp of the variola major virus strain India-1967 located on the right terminus of the conservative genome region.

Computer analysis of a variola major virus (VAR) genomic fragment bounded by the open reading frames (ORFs) D1R and A33L, which is 47,961 bp long, revealed 46 potential ORFs. The VAR proteins were compared to the analogous proteins of vaccinia virus strain Copenhagen. The subunits of DNA-dependent RNA polymerase, as well as the transcription factors, mRNA-capping enzymes, and proteins necessary for the virion morphogenesis proved to be highly conservative within orthopoxviruses. The most pronounced differences between the VAR genome fragment under study and the corresponding vaccinia virus fragment were revealed in the vicinity of the gene encoding the A-type inclusion bodies protein. Possible functions of the analysed viral proteins are discussed.

Amino Acid Sequence↗
PubMed1994

Analysis of the nucleotide sequence of 53 kbp from the right terminus of the genome of variola major virus strain India-1967.

Sequencing and computer analysis of a variola major virus strain India-1967 (VAR-IND) genome segment (53,018 bp) from the right terminal region has been carried out. Fifty-nine potential open reading frames (ORFs) of over 60 amino acid residues were identified. Structure-function organization of the VAR-IND DNA segment was compared with the previously reported sequences from the analogous genomic regions of vaccinia virus strains Copenhagen (VAC-COP) and Western Reserve (VAC-WR) and variola virus strain Harvey (VAR-HAR). Multiple differences between VAR-IND and the strains of VAC but the high identity of VAR-IND with VAR-HAR in the genetic maps are revealed. Possible functions of the predicted viral proteins and the effect of their differences on the features of orthopoxviruses are discussed.

Amino Acid Sequence↗
PubMed1993

Comparison of the genetic maps of variola and vaccinia viruses.

The complete genetic map of the variola major virus strain India-1967 is built basing on the sequence data. The suggested map is compared with the maps of the sequenced genomic regions of Copenhagen and Western Reserve strains of vaccinia virus and Harvey strain of variola major virus. The principle differences revealed in the genomic organization of these viruses are discussed.

DNA, Viral↗
PubMed1993

Analysis of the nucleotide sequence of a 43 kbp segment of the genome of variola virus India-1967 strain.

Sequencing and computer analysis of the nucleotide sequence of the variola virus strain India-1967 (VAR) genome segment (43069 bp) from the region of HindIII C, E, R, Q, K, H DNA fragments has been carried out. Forty-three potential open reading frames (ORFs) have been identified, and the polypeptides encoded by them have been compared with the analogous proteins of vaccinia virus strain Copenhagen (COP). ORF E7R of VAR is much shorter than the COP analog. The other polypeptides coded by the potential ORFs of VAR are highly conserved in comparison with COP. Possible functions of the predicted viral polypeptides are discussed.

African Swine Fever Virus↗
PubMed1993

Nucleotide sequence analysis of variola virus HindIII M, L, I genome fragments.

DNA of the variola major virus strain India-1967 in the region of HindIII M, L, I fragments has been sequenced. Analysis of this sequence of 18029 bp revealed 19 potential open reading frames (ORFs). Four proposed proteins (L2R, H9R, L5L, L6R) contain metal-binding domains. Comparison of the variola virus (VAR) and vaccinia virus strain Copenhagen (COP) sequences show that the main differences are between proteins L1R and I5R. L1R contains 6 additional amino acid residues on the C-terminus. The protein I5R of VAR contains three Ca2+ binding domains but this COP has deletions in 2 of the 3 established domains. Possible functions of the predicted viral polypeptides are discussed.

Amino Acid Sequence↗