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At least 55 records · Page 3Linked to original sources
PubMed2000

Human NB-2 of the contactin subgroup molecules: chromosomal localization of the gene (CNTN5) and distinct expression pattern from other subgroup members.

NB-2 is one of the neural recognition molecules in the contactin subgroup, which belongs to the immunoglobulin superfamily. In rat, the six molecules in this subgroup that have been reported to date are contactin, TAG-1, BIG-1, BIG-2, NB-2, and NB-3. We have isolated cDNAs encoding the two splicing isoforms of human NB-2. The long isoform of human NB-2 consists of 1100 amino acids residues that are 91% homologous to rat NB-2 at the amino acid sequence level. The short isoform lacks 74 amino acid residues between residues 19 and 93 of the long isoform. Among various regions of the adult human brain, high-level expression of NB-2 was detected in the amygdala and occipital lobe, whereas expression was low in the corpus callosum, caudate nucleus, and spinal cord. Although there were some differences, the expression pattern of NB-2 was the most similar to that of BIG-1 in the brain. Likewise, contactin and BIG-2 exhibited similar expression patterns. The expression of TAG-1 showed the least regional differences. The human NB-2 gene (CNTN5) was mapped to chromosome 11q21-q22.2 by fluorescence in situ hybridization. Our results suggest that the NB-2 gene may contribute to human neurological disorders.

Alternative Splicing↗
PubMed1977

Genetic control of resistance to subgroup A and subgroup C tumour viruses in Rhode Island Red fowl: evidence for linkage between the tumour virus a (tva) and tumour virus c (tvc) loci.

A study, using the Rhode Island Red (RIR) strain of fowl maintained at Houghton Poultry Research Station, was made to investigate the genetic control of cellular response to infection with viruses of subgroups A and C. Family matings within the RIR strain and test-crosses between the RIR parents and White Leghorn (WL) parents of known ararcrcr genotype were set up to ascertain linkage between the tumour virus a (tva) and tumour virus c (tvc) loci. The results confirmed that in this RIR strain, the two loci, tva and tvc, control the cellular response to viruses of subgroups A and C, respectively, as reported in other breeds of fowl (WL and New Hampshire). As in WL fowl, the two loci are linked. The linkage value of 0-22 in the male sex agreed well with that reported in the WL male sex, indicating that the two loci are located in the same sites in homologous chromosomes in the two breeds. However, in the RIR strain, no sex difference in crossing over between the two linked loci was found, contrary to that reported in WL fowl where the absence of crossing over between the two loci was observed in the heterogametic female sex.

Animals↗
PubMed1995

Region E3 of subgroup B human adenoviruses encodes a 16-kilodalton membrane protein that may be a distant analog of the E3-6.7K protein of subgroup C adenoviruses.

There is an open reading frame in the E3 transcription unit of adenovirus type 3 (Ad3) and Ad7 that could encode a protein of 16 kDa (16K protein). Ad3 and Ad7 are members of subgroup B of human adenoviruses. Using a rabbit antipeptide antiserum, we show that the 16K protein is expressed in Ad3- and Ad7-infected cells at early and late stages of infection; it is not expressed in cells infected with an Ad7 mutant that deletes the 16K gene. The 16K protein was also transcribed and translated in vitro from DNA containing the open reading frame for the 16K protein. The 16K protein has two hydrophobic domains typical of integral membrane proteins; consistent with this, we detected 16K in the crude membrane but not the cytosol cellular fractions. Although 16K has two potential sites for Asn-linked glycosylation, the protein is not glycosylated. The 16K gene is located in the same position in region E3 as the gene for the 6.7K protein of subgroup C adenoviruses (Ad2 and Ad5). E3-6.7K is an Asn-linked integral membrane glycoprotein, localized in the endoplasmic reticulum, whose function is unknown. The 16K protein has a putative transmembrane domain located in the same place in 16K as is the transmembrane domain in 6.7K, and the C-terminal portion of 16K is partially homologous to the C-terminal cytoplasmic domain of 6.7K; we suggest that these domains in 16K and 6.7K may have a similar function. The N-terminal 102 residues in 16K are not found in 6.7K; these residues may have a function that is unique to the 16K protein. In common with all known E3 proteins, the 16K protein is dispensable for virus replication in cultured cells; this suggests that the 16K protein may function in virus-host interactions.

Adenoviruses, Human↗
PubMed1986

Nucleotide sequences of a feline leukemia virus subgroup A envelope gene and long terminal repeat and evidence for the recombinational origin of subgroup B viruses.

Molecular clones of the subgroup A feline leukemia virus FeLV-A/Glasgow-1 have been obtained. Nucleotide sequence analysis of the 3' end of the proviral genome and comparison with the published sequence of FeLV-B/Gardner-Arnstein showed that the most extensive differences are located within the 5' domain of the env gene. Within this domain, several divergent regions of env are separated by more conserved segments. The 3' end of env is highly conserved, with only a single amino acid coding difference in p15env. The proviral long terminal repeats are also highly conserved, differing by only eight base substitutions and one base insertion. Specific probes constructed from the FeLV-A or FeLV-B env genes were used to compare the env genes of various exogenous FeLV isolates and the endogenous FeLV-related proviruses of normal cat DNA. An FeLV-A-derived env probe showed no hybridization to normal cat DNA but detected all FeLV-A and FeLV-C isolates tested. In contrast, an FeLV-B env probe detected independent FeLV-B isolates and a family of endogenous FeLV-related proviruses. Our observations provide strong evidence to support the hypothesis that FeLV-B viruses have arisen by recombination between FeLV-A and endogenous proviral elements in cat DNA.

Antigens, Viral↗
PubMed2004

Conserved CTL epitopes on the adenovirus hexon protein expand subgroup cross-reactive and subgroup-specific CD8+ T cells.

Adenoviruses often cause lethal infections in immunocompromised individuals. Adoptive transfer of immune T cells offers a therapeutic option, but this strategy has been hindered by the paucity of information on molecular targets of cellular immunity and by the immunologic heterogeneity of the 51 human adenoviruses, which are grouped from A to F on the basis of genome size, composition, homology, and organization. Clonal analysis of the adenovirus-specific cytotoxic T lymphocyte (CTL) responses of seropositive individuals identified 5 novel CD8(+) T-cell epitopes, all located in conserved regions of the capsid protein hexon. Reactive T cells were cross-reactive between 2 to 4 groups, while no T cells specific for a single subgroup were detected. Thus, by exploiting these peptide targets, it is possible to prepare a T-cell population capable of reacting with most adenoviruses that cause disease in immunocompromised patients.

Adenoviridae↗
PubMed2004

Independent origins of subgroup Bl + B2 and subgroup B3 metallo-beta-lactamases.

The metallo-beta-lactamases constitute Class B in the Ambler classification of beta-lactamases and are divided into three subclasses: Bl, B2, and B3. Bayesian phylogenies of the Subclass B1 + B2 and Subclass B3 metallo-beta-lactamases and their homologs show that the beta-lactam-hydrolyzing function evolved independently within each group. In Subclass B1+B2 that function evolved about 1 billion years ago, and in Subclass B3 it evolved before the divergence of the Gram-positive and Gram-negative eubacteria, about 2 billion years ago. These results lend additional support to the proposal that the metallo-beta-lactamases should be divided into two distinct classes.

Archaea↗
PubMed1988

The role of the two E1a mRNA products of subgroup B adenoviruses in the regulation of early promoters of subgroup C adenoviruses.

HeLa cells were co-transfected with recombinant plasmids carrying adenovirus (Ad)2 or Ad3 E1a promoters fused to the chloramphenicol acetyl transferase gene (cat), and a plasmid encoding the Ad3 E1a promoter. Whereas no stimulating effect was observed on the Ad3 E1a promoter, the Ad2 promoter was inhibited. To determine which of the E1a gene products of Ad3 was responsible for the repressive effect, plasmids were constructed in which only the 13S or 12S mRNA product of Ad3 was expressed. Both the 12S and 13S mRNA products of Ad3 E1a were found to depress the transcription from the Ad2 E1a promoter. Each Ad3 E1a gene product was able to stimulate transcription from the Ad5 E2a early promoter in a manner similar to that of the Ad2 E1a gene products. In the case of the Ad5 E3 promoter, neither of the Ad3 E1a gene products stimulated transcription, but an inhibition was observed. These results suggest that both mRNA products of the Ad3 E1a region inhibit transcription at the TATA box transcription complex.

Adenovirus Early Proteins↗
PubMed1994

c-Jun N-terminal phosphorylation correlates with activation of the JNK subgroup but not the ERK subgroup of mitogen-activated protein kinases.

c-Jun transcriptional activity is stimulated by phosphorylation at two N-terminal sites: Ser-63 and -73. Phosphorylation of these sites is enhanced in response to a variety of extracellular stimuli, including growth factors, cytokines, and UV irradiation. New members of the mitogen-activated protein (MAP) kinase group of signal-transducing enzymes, termed JNKs, bind to the activation domain of c-Jun and specifically phosphorylate these sites. However, the N-terminal sites of c-Jun were also suggested to be phosphorylated by two other MAP kinases, ERK1 and ERK2. Despite these reports, we find that unlike the JNKs, ERK1 and ERK2 do not phosphorylate the N-terminal sites of c-Jun in vitro; instead they phosphorylate an inhibitory C-terminal site. Furthermore, the phosphorylation of c-Jun in vivo at the N-terminal sites correlates with activation of the JNKs but not the ERKs. The ERKs are probably involved in the induction of c-fos expression and thereby contribute to the stimulation of AP-1 activity. Our study suggests that two different branches of the MAP kinase group are involved in the stimulation of AP-1 activity through two different mechanisms.

Animals↗
PubMed2006

Susceptibility of various parental lines of commercial white leghorn layers to infection with a naturally occurring recombinant avian leukosis virus containing subgroup B envelope and subgroup J long terminal repeat.

Chickens from seven different parental lines of commercial White Leghorn layer flocks from three independent breeders were inoculated with a naturally occurring avian leukosis virus (ALV) containing an ALV-B envelope and an ALV-J long terminal repeat (LTR) termed ALV-B/J. Additional groups of chickens from the same seven parental lines were inoculated with ALV-B. Chickens were tested for ALV viremia and antibody at 0, 4, 8, 16, and 32 wk postinfection. Chickens from all parental lines studied were susceptible to infection with ALV-B with 40%-100% of inoculated chickens positive for ALV at hatch following embryo infection. Similarly, infection of egg layer flocks with the ALV-B/J recombinant virus at 8 days of embryonation induced tolerance to ALV with 86%-100% of the chickens viremic, 40%-75% of the chickens shedding virus, and only 2/125 (2%) of the chickens producing serum-neutralizing antibodies against homologous ALV-B/J recombinant virus at 32 wk postinfection. In contrast, when infected with the ALV-B/J recombinant virus at hatch, 33%-82% of the chickens were viremic, 28%-47% shed virus, and 0%-56% produced serum-neutralizing antibodies against homologous ALV-B/J recombinant virus at 32 wk postinfection. Infection with the ALV-B/J recombinant virus at embryonation and at hatch induced predominately lymphoid leukosis (LL), along with other common ALV neoplasms, including erythroblastosis, osteopetrosis, nephroblastomas, and rhabdosarcomas. No incidence of myeloid leukosis (ML) was observed in any of the commercial White Leghorn egg layer flocks infected with ALV-B/J in the present study. Data suggest that the parental line of commercial layers may influence development of ALV-B/J-induced viremia and antibody, but not tumor type. Differences in type of tumors noted in the present study and those noted in the field case where the ALV-B/J was first isolated may be attributed to differences in the genetics of the commercial layer flock in which ML was first diagnosed and the present commercial layer flocks tested in the present study.

Animals↗