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PubMed1993

Differential expression of distinct mRNAs for ovine trophoblast protein-1 and related sheep type I interferons.

An antiluteolytic substance secreted by the ovine conceptus and primarily responsible for maternal recognition of pregnancy is ovine trophoblast protein-1 (oTP-1), a new type I interferon (IFN). The objectives of this research were 1) to investigate whether multiple, distinct genes encode oTP-1 and other type I IFNs in the ovine genome and 2) to examine expression of oTP-1 and other IFN mRNAs during conceptus development. Genes for type I IFNs were isolated from a subgenomic library constructed from Day 25 (Day 0 = estrus) ovine conceptus high-molecular-weight DNA. Six clones were isolated and nucleotide-sequenced from -1000 to +900 (bases relative to cap site). Comparisons of inferred amino acid sequences demonstrated that four clones were distinct oTP-1 genes and that two clones, defined as o9 and o12, were related type 1 IFNs (deduced aa homology of o9 and o12 to oTP-1 was 71% and 54%, respectively). The presence of mRNAs encoded by oTP-1 and type I IFN genes was examined quantitatively via reverse transcription-polymerase chain reaction (RT-PCR) analysis of total cellular RNA (tcRNA) extracted from Day 13-45 concepti. Total cellular RNA obtained from Day 75 placenta and adult lymphocytes was also analyzed by RT-PCR, coupled with Southern blot hybridization of the PCR reaction products with specific DNA probes. PCR products were sequenced in order to confirm primer specificity, and mRNAs corresponding to two of the four oTP-1 genes and to both related IFN clones (o9 and o12) were identified. Furthermore, quantitation of the PCR products revealed that of the two oTP-1 genes examined, one was highly expressed on Days 13-20 and transcripts were weakly detectable on Days 30 and 45. In contrast, the other oTP-1 gene examined was weakly expressed on Days 13-20 only. Densitometric analysis of hybridization signals revealed that IFN o9 mRNA was detected in Day 75 placenta but only weakly detected in conceptus (Days 13-45) and adult lymphocytes. IFN o12 mRNA was abundant in lymphocytes relative to the other tissues examined. Collectively, these results demonstrate the existence of distinct oTP-1 and related type I IFN genes. The data suggest that these genes display differential, tissue-specific expression and developmental regulation during pregnancy.

Amino Acid Sequence↗
PubMed1990

The major subunit of Escherichia coli type 1 fimbriae is not required for D-mannose-specific adhesion.

Type 1 fimbriae are surface organelles on Escherichia coli, which mediate specific binding to D-mannose-containing structures. These fimbriae are heteropolymers composed of a major building element, the FimA protein, and small amounts of the FimF, FimG and FimH proteins. The FimH protein is uniquely responsible for the D-mannose receptor binding. In this work data are presented which indicate that the major subunit of type 1 fimbriae is dispensable for D-mannose-specific binding. A recombinant strain was studied which harboured an insertional deletion in the fimA gene, and was thereby unable to produce type 1 fimbriae; however, it was still able to express a D-mannose-binding phenotype. However, the deletion resulted in a 25-fold reduction of the adhesive potential, as measured by binding to D-mannose-coated Sepharose beads. Serological and specific receptor binding evidence is presented that suggests that the FimH adhesion is capable of being exposed on the bacterial surface without being an integral part of the fimbriae.

Animals↗
PubMed1996

Glycopeptide susceptibility among Danish Enterococcus faecium and Enterococcus faecalis isolates of animal and human origin and PCR identification of genes within the VanA cluster.

The MICs of vancomycin and avoparcin were determined for isolates of Enterococcus faecium and isolates of Enterococcus faecalis recovered from the feces of humans and animals in Denmark. Two hundred twenty-one of 376 (59%) isolates of E. faecium and 2 of 133 (1.5%) isolates of E. faecalis were resistant to vancomycin (MICs, 128 to > or = 256 micrograms/ml), and all vancomycin-resistant isolates were resistant to avoparcin (MICs, 64 to > or = 256 micrograms/ml). All vancomycin-resistant isolates examined carried the vanA, vanX, and vanR genes, suggesting that a gene cluster similar to that of the transposon Tn1546 was responsible for the resistance.

Animals↗
PubMed1999

The periplasmic nitrate reductase in Pseudomonas sp. strain G-179 catalyzes the first step of denitrification.

Both membrane-bound and periplasmic nitrate reductases have been found in denitrifying bacteria. Yet the role of periplasmic nitrate reductase in denitrification has not been clearly defined. To analyze the function of the periplasmic nitrate reductase in Pseudomonas sp. strain G-179, the nap gene cluster was identified and found to be linked to genes involved in reduction of nitrite and nitric oxide and anaerobic heme biosynthesis. Mutation in the nap region rendered the cells incapable of growing under anaerobic conditions with nitrate as the alternative electron acceptor. No nitrate reduction activity was detected in the Nap- mutant, but that activity could be restored by complementation with the nap region. Unlike the membrane-bound nitrate reductase, the nitrate reduction activity in strain G-179 was not inhibited by a low concentration of azide. Nor could it use NADH as the electron donor to reduce nitrate or use chlorate as the alternative substrate. These results suggest that the periplasmic nitrate reductase in this strain plays a primary role in dissimilatory nitrate reduction.

Bacterial Typing Techniques↗
PubMed2005

DNA polymorphism and molecular subtyping of the capsular gene cluster of group B streptococcus.

Serotyping and other phenotypic methods are often used to characterize the capsular polysaccharide of group B streptococci (GBS). We describe a capsular genotyping method that utilizes PCR of capsular polysaccharide synthesis genes (cps) and restriction enzyme digestion. This method facilitates the detection of DNA polymorphism in cps genes and correlates well with serotyping.

Bacterial Capsules↗
PubMed1996

Bacterial diversity based on type II DNA topoisomerase genes.

Type II DNA topoisomerases are essential and ubiquitous DNA metabolic enzymes that alter DNA topology. Eubacteria have two indispensable type II DNA topoisomerases, DNA gyrase encoded by gyrB and gyrA and topoisomerase IV encoded by parE and parC. These genes belong to a single family whose members span both eukaryotes and prokaryotes. The highly conserved motifs in these genes provide a rationale for the design of universal primers used in the polymerase chain reaction in order to systematically generate a data set suitable for bacterial diversity studies at the macro-diversity level, as well as at the micro-diversity level displaying individual species and isolates. This family of genes is the subject of intensive biochemical and genetic analyses, which provide an opportunity for comprehensive understanding of sequence conservation and variability and their relationship to function. These genes are ideally suited for microbial identification and biodiversity analyses.

Amino Acid Sequence↗
PubMed1995

Cyclic nucleotide phosphodiesterases: functional implications of multiple isoforms.

In the last few years there has been a veritable explosion of knowledge about cyclic nucleotide phosphodiesterases. In particular, the accumulating data showing that there are a large number of different phosphodiesterase isozymes have triggered an equally large increase in interest about these enzymes. At least seven different gene families of cyclic nucleotide phosphodiesterase are currently known to exist in mammalian tissues. Most families contain several distinct genes, and many of these genes are expressed in different tissues as functionally unique alternative splice variants. This article reviews many of the more important aspects about the structure, cellular localization, and regulation of each family of phosphodiesterases. Particular emphasis is placed on new information obtained in the last few years about how differential expression and regulation of individual phosphodiesterase isozymes relate to their function(s) in the body. A substantial discussion of the currently accepted nomenclature is also included. Finally, a brief discussion is included about how the differences among distinct phosphodiesterase isozymes are beginning to be used as the basis for developing therapeutic agents.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1994

Expression and regulation of Ly-6 differentiation antigens by murine osteoblasts.

Osteoblasts arise from mesenchymal stem cells and differentiate to become osteoid-secreting cells. However, little is known about these cells during their stages of differentiation. One reason for this lack of information is that there is no reliable method to identify osteoblasts as they mature. One method that has been used successfully with other cell types is the identification of plasma membrane-expressed differentiation antigens. The Ly-6 multigene family encodes differentiation antigens originally detected on lymphoid cells. Primary murine osteoblasts and the osteoblast-like MC3T3 cell line were examined for expression of Ly-6 antigens by flow cytometry. Primary osteoblasts and MC3T3 cells constitutively expressed both Ly-6A and Ly-6C antigens, although Ly-6C was much less abundant. Antigen expression was markedly increased by pretreating the cells with interferon-alpha/beta or -gamma. Northern blot analysis revealed constitutively expression of Ly-6 messenger RNA that was up-regulated by interferon treatment. Pretreatment of the cells with transforming growth factor-beta 1 or 1,25-dihydroxyvitamin D3 diminished constitutive Ly-6 expression. Ly-6 was localized intracellularly to the Golgi complex. The current results demonstrate that mature osteoblasts express on their cell surface specific Ly-6 antigens in a pattern that distinguishes them from the surrounding bone marrow cells. These studies represent the first identification of osteoblast differentiation antigens that can be directly related to cells within the hematopoietic lineage. By identifying similar antigens, osteoblasts at various stages of differentiation may be identified, isolated, and characterized.

Animals↗
PubMed2003

Cumulative Toll-like receptor activation in human macrophages treated with whole bacteria.

Purified components from bacteria selectively activate Toll-like receptors (TLR), leading to shared and unique responses in innate immune cells. Whole bacteria contain agonists for multiple TLR and induce a common macrophage activation program of transcription. It is not known, however, whether the stimulation of specific TLR by whole bacteria results in differential activation of the innate immune system. We evaluated gene expression data from human macrophages and found a unique gene expression profile induced by Gram-negative bacteria. In contrast, Gram-positive bacteria evoked few specific alterations in gene expression. LPS, a TLR4-specific ligand, was sufficient to elicit the distinct expression profile observed with Gram-negative bacteria. TLR4 activation regulated gene expression by both an IFN-dependent and an IFN-independent mechanism, illustrated by I-TAC and IL-12 p70, respectively. IL-12 p70 was produced by cells in whole blood exposed to Gram-negative bacteria, demonstrating faithful reproduction of the macrophage response in mixed populations of cells and identifying a potential diagnostic marker of infection. Our results show that the macrophage response to bacteria is dominated by the accumulated input from multiple TLR. For macrophages exposed to Gram-negative bacteria, gene expression changes encompass those induced by Gram-positive bacteria plus a distinct TLR4 response. This distinct TLR4 response may provide the basis to diagnose clinical Gram-negative infections.

Cells, Cultured↗
PubMed2006

Cmv4, a new locus linked to the NK cell gene complex, controls innate resistance to cytomegalovirus in wild-derived mice.

CMV can cause life-threatening disease in immunodeficient hosts. Experimental infection in mice has revealed that the genetically determined natural resistance to murine CMV (MCMV) may be mediated either by direct recognition between the NK receptor Ly49H and the pathogen-encoded glycoprotein m157 or by epistatic interaction between Ly49P and the host MHC H-2D(k). Using stocks of wild-derived inbred mice as a source of genetic diversity, we found that PWK/Pas (PWK) mice were naturally resistant to MCMV. Depletion of NK cells subverted the resistance. Analysis of backcrosses to susceptible BALB/c mice revealed that the phenotype was controlled by a major dominant locus effect linked to the NK gene complex. Haplotype analysis of 41 polymorphic markers in the Ly49h region suggested that PWK mice may share a common ancestral origin with C57BL/6 mice; in the latter, MCMV resistance is dependent on Ly49H-m157 interactions. Nevertheless, PWK mice retained viral resistance against m157-defective mutant MCMV. These results demonstrate the presence of yet another NK cell-dependent viral resistance mechanism, named Cmv4, which most likely encodes for a new NK activating receptor. Identification of Cmv4 will expand our understanding of the specificity of the innate recognition of infection by NK cells.

Amino Acid Sequence↗
PubMed2000

A genomics approach to the comprehensive analysis of the glutathione S-transferase gene family in soybean and maize.

By BLAST searching a large expressed sequence tag database for glutathione S-transferase (GST) sequences we have identified 25 soybean (Glycine max) and 42 maize (Zea mays) clones and obtained accurate full-length GST sequences. These clones probably represent the majority of members of the GST multigene family in these species. Plant GSTs are divided according to sequence similarity into three categories: types I, II, and III. Among these GSTs only the active site serine, as well as another serine and arginine in or near the "G-site" are conserved throughout. Type III GSTs have four conserved sequence patches mapping to distinct structural features. Expression analysis reveals the distribution of GSTs in different tissues and treatments: Maize GSTI is overall the most highly expressed in maize, whereas the previously unknown GmGST 8 is most abundant in soybean. Using DNA microarray analysis we observed increased expression among the type III GSTs after inducer treatment of maize shoots, with different genes responding to different treatments. Protein activity for a subset of GSTs varied widely with seven substrates, and any GST exhibiting greater than marginal activity with chloro-2,4 dinitrobenzene activity also exhibited significant activity with all other substrates, suggesting broad individual enzyme substrate specificity.

Cloning, Molecular↗
PubMed1995

A novel transcription factor and two members of the Sp 1 multigene family regulate the activity of the alpha 2 (VI) collagen promoter.

For a better understanding of the processes that lead to the activation or inhibition of type VI collagen synthesis, we have identified and characterized the cis-acting elements of the chicken alpha 2 (VI) collagen promoter. This promoter encompasses four sites, termed S1, S2, X and S3, which interact with nuclear factors. Sites S1, S2 and S3 are each recognized by the same two proteins that belong to the Sp 1 multigene family. Site X appears to interact with a novel transcription factor of 43 kDa. When a fragment containing all four of the elements is placed in front of a reporter gene, the resulting construct is able to induce a high level of transcription in chicken fibroblasts. As soon as a single element is deleted from this construct, the activity decreases drastically. Thus, the four elements are essential for the transcriptional activation of the alpha 2 (VI) collagen gene.

Animals↗
PubMed2002

Mosaic-like transcription of var genes in single Plasmodium falciparum parasites.

The var gene family of Plasmodium falciparum encodes the clonally variant adhesin PfEMP1 present on the surface of infected erythrocytes. A poorly understood mechanism of allelic exclusion controls the expression of PfEMP1. Transcription of var genes is developmentally and, most likely, epigenetically regulated. Here we have studied the transcriptional pattern of 28 members of this multigene family in individual parasites, early in the intraerythrocytic cycle. The results show unique patterns (type and number) of var transcripts in each individual PRBC, with 1-15 mRNA species detected per cell at 2-4 h post-invasion. When a panel of ten single PRBC was analyzed, the var gene coding for the expressed PfEMP1 was transcribed in more cells than any other, although transcripts from this gene did not give the strongest hybridization signal within each individual cell. Chromosomal mapping of transcriptionally active var genes indicated that their distribution reflects that of var loci in the genome, including a pronounced clustering in chromosome 4. These findings, taken together with existing data on var transcription at later developmental stages, suggest that the mosaic-like transcription of multiple var genes detected at the ring stage and the steady transcription of the gene encoding the expressed PfEMP1 are distinct although superimposed events, one of them random and the other taking place under some form of imprinting. With its unique features, the expression of P. falciparum var genes may reveal new principles of gene regulation.

Amino Acid Sequence↗
PubMed2005

Barley Dhn13 encodes a KS-type dehydrin with constitutive and stress responsive expression.

Dehydrins (DHNs) compose a family of intrinsically unstructured proteins that have high water solubility and accumulate during late seed development, low temperature or water deficit conditions, and are thought to play a protective role in freezing and drought tolerance in plants. Twelve Dhn genes were previously described in the barley genome. Here, we report an additional member of this multigene family, Dhn13. The Dhn13 gene is located in chromosome 4 near marker MWG634 and encodes a 107-amino acid KS-type DHN. Semi-quantitative reverse transcriptase PCR data indicated that Dhn13 is constitutively expressed in seedling tissues and embryos of developing seeds. Microarray data were consistent with these results and showed a considerable increase of Dhn13 transcripts when plants were subjected to chilling and freezing temperatures. The highest transcript levels where observed in anthers. The presence of ABRE, MYC, DRE, and POLLEN1LELAT52 regulatory elements in the putative Dhn13 promoter region is in agreement with expression data.

Amino Acid Sequence↗
PubMed2005

Multigene phylogenetic analysis of pathogenic candida species in the Kazachstania (Arxiozyma) telluris complex and description of their ascosporic states as Kazachstania bovina sp. nov., K. heterogenica sp. nov., K. pintolopesii sp. nov., and K. slooffiae sp. nov.

A yeast causing widespread infection of laboratory mice was identified from 26S rRNA gene sequences as Candida pintolopesii. To determine the relationship of C. pintolopesii with other members of the Kazachstania (Arxiozyma) telluris species complex, nucleotide sequences from domains 1 and 2 of the 26S rRNA gene, the mitochondrial small-subunit rRNA gene, and the RNA polymerase II gene were phylogenetically analyzed. That analysis resolved the 48 strains examined into five closely related species: K. telluris, Candida bovina, C. pintolopesii, Candida slooffiae, and a previously unknown species. One or more strains of each of the last four species formed an ascosporic state much like that of K. telluris. To place these ascosporogenous strains taxonomically, it is proposed that they be assigned to the teleomorphic genus Kazachstania as K. bovina (type strain NRRL Y-7283, CBS 9732, from the nasal passage of a pigeon), K. heterogenica (type strain NRRL Y-27499, CBS 2675, from rodent feces), K. pintolopesii (type strain NRRL Y-27500, CBS 2985, from the peritoneal fluid of a dead guinea pig), and K. slooffiae (type strain NRRL YB-4349, CBS 9733, from the cecum of a horse). On the basis of multigene sequence analyses, K. heterogenica appears to be a hybrid of K. pintolopesii and a presently unknown species. With the exception of K. bovina, the phylogenetically defined species show a moderate degree of host specificity.

Animals↗
PubMed1996

The cellular Internet: on-line with connexins.

Most cells communicate with their immediate neighbors through the exchange of cytosolic molecules such as ions, second messengers and small metabolites. This activity is made possible by clusters of intercellular channels called gap junctions, which connect adjacent cells. In terms of molecular architecture, intercellular channels consist of two channels, called connexons, which interact to span the plasma membranes of two adjacent cells and directly join the cytoplasm of one cell to another. Connexons are made of structural proteins named connexins, which compose a multigene family. Connexin channels participate in the regulation of signaling between developing and differentiated cell types, and recently there have been some unexpected findings. First, unique ionic- and size-selectivities are determined by each connexin; second, the establishment of intercellular communication is defined by the expression of compatible connexins; third, the discovery of connexin mutations associated with human diseases and the study of knockout mice have illustrated the vital role of cell-cell communication in a diverse array of tissue functions.

Amino Acid Sequence↗
PubMed2003

Intracellular and extracellular roles of S100 proteins.

S100, a multigenic family of non-ubiquitous Ca(2+)-modulated proteins of the EF-hand type expressed in vertebrates exclusively, has been implicated in intracellular and extracellular regulatory activities. Members of this protein family have been shown to interact with several effector proteins within cells thereby regulating enzyme activities, the dynamics of cytoskeleton constituents, cell growth and differentiation, and Ca(2+) homeostasis. Structural information indicates that most of S100 proteins exist in the form of antiparallelly packed homodimers (in some cases heterodimers), capable of functionally crossbridging two homologous or heterologous target proteins in a Ca(2+)-dependent (and, in some instances, Ca(2+)-independent) manner. In addition, extracellular roles have been described for several S100 members, although secretion (via an unknown mechanism) has been documented for a few of them. Extracellular S100 proteins have been shown to exert regulatory effects on inflammatory cells, neurons, astrocytes, microglia, and endothelial and epithelial cells, and a cell surface receptor, RAGE, has been identified as a potential S100A12 and S100B receptor transducing the effects of these two proteins on inflammatory cells and neurons. Other cell surface molecules with ability to interact with S100 members have been identified, suggesting that RAGE might not be a universal S100 protein receptor and/or that a single S100 protein might interact with more than one receptor. Collectively, these data indicate that members of the S100 protein family are multifunctional proteins implicated in the regulation of a variety of cellular activities.

Animals↗