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At least 847 records · Page 47Linked to original sources
PubMed2002

ccfA, the genetic determinant for the cCF10 peptide pheromone in Enterococcus faecalis OG1RF.

The nosocomial pathogen Enterococcus faecalis has a unique pheromone-inducible conjugative mating system. Conjugative transfer of the E. faecalis plasmid pCF10 is specifically induced by the cCF10 peptide pheromone (LVTLVFV). Genomic sequence information has recently allowed the identification of putative structural genes coding for the various enterococcal pheromones (D. B. Clewell et al., Mol. Microbiol. 35:246-247, 2000). The cCF10 pheromone sequence LVTLVFV was found within an open reading frame designated ccfA, encoding a putative lipoprotein precursor. Several other pheromone sequences were found in similar locations within other predicted lipoproteins. CcfA shows significant sequence relatedness to the Escherichia coli protein YidC, an inner membrane protein translocase, as well as to a large number of homologs identified in gram-positive and in gram-negative bacteria. Analysis of the deduced CcfA amino acid sequence suggested that mature cCF10 peptide could be formed from the proteolytic degradation of its signal peptide. Expression of the cloned ccfA gene with an inducible expression vector dramatically increased cCF10 production by E. faecalis and also resulted in cCF10 production by Lactococcus lactis, a non-pheromone producer. Site-directed mutagenesis of the ccfA sequence encoding the cCF10 peptide confirmed that ccfA was a functional genetic determinant for cCF10.

Amino Acid Sequence↗
PubMed1999

BAC-mediated gene-dosage analysis reveals a role for Zipro1 (Ru49/Zfp38) in progenitor cell proliferation in cerebellum and skin.

Genetic analysis in mice has most commonly employed two general strategies: phenotypic screens for spontaneous or induced mutations and genotypic analysis using homologous recombination or gene trapping to produce deletion or insertion mutants. Here we use bacterial artificial chromosome (BAC)-mediated gene-dosage analysis in transgenic mice to reveal novel genetic functions that are not evident from conventional loss-of-function mutations. We demonstrate a role for the zinc-finger transcription factor Zipro1 (formerly Ru49 and Zfp38) in the proliferation of granule cell precursors in the developing cerebellum, and document the contribution of this process to the final stages of cerebellar morphogenesis. We also show that Zipro1 is expressed in skin, and increased Zipro1 dosage results in a hair-loss phenotype associated with increased epithelial cell proliferation and abnormal hair follicle development.

Animals↗
PubMed2005

The CARD-carrying caspase Dronc is essential for most, but not all, developmental cell death in Drosophila.

The initiator caspase Dronc is the only Drosophila caspase that contains a caspase activation and recruitment domain (CARD). Although Dronc has been implicated as an important effector of apoptosis, the genetic function of dronc in normal development is unclear because dronc mutants have not been available. In an EMS mutagenesis screen, we isolated four point mutations in dronc that recessively suppress the eye ablation phenotype caused by eye-specific overexpression of hid. Homozygous mutant dronc animals die during pupal stages; however, at a low frequency we obtained homozygous adult escapers. These escapers have additional cells in the eye and wings that are less transparent and slightly curved down. We determined that this is due to lack of apoptosis. Our analyses of dronc mutant embryos suggest that dronc is essential for most apoptotic cell death during Drosophila development, but they also imply the existence of a dronc-independent cell death pathway. We also constructed double mutant flies for dronc and the apoptosis inhibitor diap1. dronc mutants can rescue the ovarian degeneration phenotype caused by diap1 mutations, confirming that dronc acts genetically downstream of diap1.

Alleles↗
PubMed1998

Direct selection cloning vectors adapted to the genetic analysis of gram-negative bacteria and their plasmids.

A range of specific and unusual biological pathways are found in Gram-negative bacteria. It is possible to express the genes involved in these processes in Escherichia coli, however, some genes prove lethal when cloned into high copy number vectors in common usage. Conversely, various genetic functions remain silent in E. coli and require to be transferred into their original host for expression and subsequent analysis. To facilitate the cloning and the characterisation of bacterial genes, we have constructed CcdB 'positive-selection' vectors that possess one or more of the following properties: (i) low or medium copy number; (ii) narrow or broad replication host range; (iii) conjugational mobilisation. In this communication, we illustrate the use of these new cloning tools and analyse the CcdB toxicity in different bacterial species.

Bacterial Proteins↗
PubMed1984

Isolation of cold-sensitive mutants of measles virus from persistently infected murine neuroblastoma cells.

Clone NS20Y of the mouse neuroblastoma C1300 was infected with wild-type Edmonston measles virus, and, after a transition to a carrier culture, became persistently infected. Persistently infected clones were derived and characterized morphologically by the appearance of multinucleate giant cells and nucleocapsid matrices in cytoplasm and nucleus, but very few budding virus particles. Antimeasles antibodies markedly suppressed the expression of viral antigens and giant cells, and the effect was totally reversible. When the cells were cultured at 33 degrees C, the number of giant cells began to diminish and ultimately disappeared; in contrast, when cultured at 39 degrees C, the cultures invariably lysed. Yields at 33 degrees C were ca. 2 logs lower than those at 39 degrees C. Cells cultured at 33 degrees C produced relatively high levels of interferon, whereas those at 39 degrees C produced little or no interferon. When the persistently infected cultures were exposed to anti-interferon alpha/beta serum at a nonpermissive temperature, there was a marked increase in multinucleate cells, suggesting that maintenance of the persistence state and its regulation by temperature may be related to the production of interferon. Viral isolates from cells cultured at 39 degrees C were obtained, and 90% of viral clones were found to be cold sensitive. Complementation studies with different viral clones indicated that the cold-sensitive defect was probably associated with the same genetic function. Western blot analysis of the persistently infected cells indicated a significant diminution and expression of all measles-specific proteins at a nonpermissive temperature. Infection of NS20Y neuroblastoma cells with the cold-sensitive virus isolates resulted in the development of an immediate persistent infection, whereas infection of Vero or HeLa cells resulted in a characteristic lytic infection, suggesting that the cold-sensitive mutants may be selected or adapted for persistent infection in cells of neural origin.

Animals↗
PubMed1999

Ectopic expression of individual E(spl) genes has differential effects on different cell fate decisions and underscores the biphasic requirement for notch activity in wing margin establishment in Drosophila.

A common consequence of Notch signalling in Drosophila is the transcriptional activation of seven Enhancer of split [E(spl)] genes, which encode a family of closely related basic-helix-loop-helix transcriptional repressors. Different E(spl) proteins can functionally substitute for each other, hampering loss-of-function genetic analysis and raising the question of whether any specialization exists within the family. We expressed each individual E(spl) gene using the GAL4-UAS system in order to analyse their effect in a number of cell fate decisions taking place in the wing imaginal disk. We focussed on sensory organ precursor determination, wing vein determination and wing pattern formation. All of the E(spl) proteins affect the first two processes in the same way, namely they antagonize neural precursor and vein fates. Yet, the efficacy of this antagonism is quite distinct: E(spl)mbeta has the strongest vein suppression effect, whereas E(spl)m8 and E(spl)m7 are the most active bristle suppressors. During wing patterning, Notch activity orchestrates a complex sequence of events that define the dorsoventral boundary of the wing. We have discerned two phases within this process based on the sensitivity of N loss-of-function phenotypes to concomitant expression of E(spl) genes. E(spl) proteins are initially involved in repression of the vg quadrant enhancer, whereas later they appear to relay the Notch signal that triggers activation of cut expression. Of the seven proteins, E(spl)mgamma is most active in both of these processes. In conclusion, E(spl) proteins have partially redundant functions, yet they have evolved distinct preferences in implementing different cell fate decisions, which closely match their individual normal expression patterns.

Animals↗
PubMed2005

Exploring 3D-QSAR of thiazole and thiadiazole derivatives as potent and selective human adenosine A3 receptor antagonists+.

Binding affinity data [Bioorg Med Chem (2004) 12:613-623] of thiazole and thiadiazole derivatives (n = 30) for the human adenosine A3 receptor subtype have been subjected to 3D-QSAR (Quantitative structure-activity relationships) analyses by molecular shape analysis (MSA) and molecular field analysis (MFA) techniques using Cerius2 Version 4.8. In the case of the MSA, the major steps were (1) generation of conformers and energy minimization; (2) hypothesizing an active conformer (global minimum of the most active compound); (3) selecting a candidate shape-reference compound (based on the active conformation); (4) performing pairwise molecular superimposition using the maximum common subgroup (MCSG) method; (5) measuring molecular shape commonality using MSA descriptors; (6) determining other molecular features by calculating spatial, electronic and conformational parameters; (7) selection of conformers; (8) generation of QSAR equations by genetic function algorithm (GFA) or stepwise regression. The best 3D-QSAR equation (MSA) obtained from GFA technique shows 70.0% predicted variance (leave-one-out) and 77.7% explained variance. This equation shows the importance of Jurs descriptors (atomic charge weighted positive surface area, relative negative charge and relative positive charge surface area), partial moment of inertia, energy of the most stable conformer and the ratio of common overlap steric volume to volume of individual molecules. In the case of stepwise regression, the best relation showed 46.1% predicted variance and 72.3% explained variance. In the case of MFA, the major steps were (1) generating conformers and energy minimization; (2) matching atoms using a maximum common substructure (MCS) search and aligning molecules using the default options; (3) setting MFA preferences (rectangular grid with 2 A step size, charges by the Gasteiger algorithm, H+ and CH3 as probes); (4) creating the field; (5) analysis by the Genetic partial least squares (G/PLS) method. The equation obtained was of excellent statistical quality: 96.1% explained variance and 71.6% predicted variance. Statistically reliable 3D-QSAR models obtained from this study suggest that these techniques could be useful to design potent A3 receptor antagonists.

Adenosine A3 Receptor Antagonists↗
PubMed2006

Association between ADAM33 polymorphisms and adult asthma in the Japanese population.

BACKGROUND: ADAM33, a member of the ADAM (a disintegrin and metalloprotease) family, is a putative asthma susceptibility gene recently identified by positional cloning. It is important to know whether the association exists in ethnically diverse populations. OBJECTIVE: To assess whether genetic functional variants of ADAM33 relate to the susceptibility or some phenotypes in adult patients with bronchial asthma in a Japanese population. METHODS: We searched for single nucleotide polymorphisms (SNPs) in ADAM33 by PCR-directed sequencing and identified 48 SNPs. Fourteen SNPs were selected with regard to the LD pattern, and genotyped by Taq-Man and PCR-RFLP methods. We conducted an association study of ADAM33 with 504 adult asthmatic patients and 651 controls, and haplotype analyses of related variants were performed. RESULTS: Significant associations with asthma were found for the SNPs T1 (Met764Thr), T2 (Pro774Ser), S2 and V-3 (with the lowest P-value for T1, P = 0.0015; OR 0.63). We analysed the haplotype using these four polymorphisms, and found a positive association with haplotype CCTG (P = 0.0024). CONCLUSION: Our results replicate associations reported recently in other ethnic populations, and suggest that the ADAM33 gene is involved in the development of asthma through genetic polymorphisms.

ADAM Proteins↗
PubMed1980

Racial differences in dimensional traits of the human face.

1. Race is difficult to define at best and references to groups are more accurately made on the basis of ethnic groups that are bound by some common bond, such as Swedish Whites, American Whites, etc. 2. The quantifiable differences in the somatic craniofacial region of ethnic groups residing for several generations in the same or similar geographic areas are small. 3. The evidence supports a geographical effect on the most frequently used quantifiable angular measurements of the somatic facial profile of the major racial groups. 4. Cephalofacial morphology is affected by many factors including genetics, function and temperature. 5. There are mean differences in the quantifiable traits of the face of some ethnic groups. The differences in means within ethnic or racial groups are often greater than the differences in means among ethnic or racial groups. 6. The differences in means of traits of the somatic facial skeleton among or between ethnic groups are usually very small with an enormous degree of overlap. 7. The parameters of the face that are closer to the alveolar and dental areas show the greatest differences among ethnic and racial groups.

Adolescent↗
PubMed1998

Benefits of pharmacological knowledge in the design and monitoring of cancer chemotherapy.

Prescribing chemotherapy is a difficult task, because of drug resistance, which prevents all tumors to respond to a given protocol and because of drug toxicity, which is generally unavoidable but which must be limited to acceptable levels. The therapeutic window of anticancer drugs is very narrow and clinicians have to try to optimize the individual doses and schedules of the drugs to be administered. They can rely upon simple anthropometric features, such as body weight or surface area; they can also take into account the physiological status of the patient: age, liver and kidney function, genetic characteristics of drug metabolism, etc. The best way for dose adaptation lies in the establishment of pharmacokinetic/pharmacodynamic relationships, i.e., between the behavior of a drug in the body and its efficacy and toxicity. When it is established that the optimal effect of a drug is related to a given parameter, such as the area under the curve plotting plasma concentration vs. time (AUC), it becomes possible to administer the drug with the dose allowing to obtain the target parameter value. Individual dose adaptation can be achieved thanks to the study of the pharmacokinetics of a test dose preceding that of the therapeutic dose, or by the measure of drug plasma levels, either at steady state during a protracted infusion, or from cycle to cycle during repetitive protocols. Population analysis now allows the adaptation of anticancer drug dosing from a minimum knowledge of individual pharmacokinetic features, together with other characteristics of the patients such as age, gender or physiological functions.

Antineoplastic Agents↗
PubMed1994

Photoactive mitochondria: in vivo transfer of a light-driven proton pump into the inner mitochondrial membrane of Schizosaccharomyces pombe.

The light-driven proton pump bacteriorhodopsin (bR) from Halobacterium salinarium has been genetically transferred into the inner mitochondrial membrane (IM) of the eukaryotic cell Schizosaccharomyces pombe, where the archaebacterial proton pump replaces or increases the proton gradient usually formed by the respiratory chain. For targeting and integration, as well as for the correct orientation of bR in the IM, the bacterioopsin gene (bop) was fused to signal sequences of IM proteins. Northern and Western blot analysis proved that all hybrid gene constructs containing the bop gene and a mitochondrial signal sequence were expressed and processed to mature bR. Fast transient absorption spectroscopy showed photocycle activity of bR integrated in the IM by formation of the M intermediate. Experiments with the pH-sensitive fluorescence dye 2',7'-bis(2-carboxyethyl)-5 (and -6)-carboxyfluorescein revealed bR-mediated proton pumping from the mitochondrial matrix into the intermembrane space. Glucose uptake measurements under anaerobic conditions showed that yeast cells containing photoactive mitochondria need less sugar under illumination. In summary, our experiments demonstrate the functional genetic transfer of a light energy converter to a naturally nonphotoactive eukaryotic organism.

Bacteriorhodopsins↗
PubMed1984

In vitro generation of specific deletions in DNA cloned in M13 vectors using synthetic oligodeoxyribonucleotides: mutants in the 5'-flanking region of the yeast alcohol dehydrogenase II gene.

Deletion mutants are particularly useful in defining the boundaries of noncoding genetic functions. Such mutants can be precisely generated using synthetic oligodeoxyribonucleotides as mutagens. In this paper we describe the application of this method to recombinant DNA cloned in a phage M13-derived vector. The mutagenic oligodeoxyribonucleotides, 20 and 21 nucleotides in length, were used to delete a tract of 20 dA-dT base-pairs and an adjacent 22 base-pair perfect dyad from the ADR3 locus, the 5'-flanking regulatory region of the ADR2 gene, of Saccharomyces cerevisiae with high efficiency.

Alcohol Dehydrogenase↗
PubMed1990

Specific expression of a silk-encoding gene of Bombyx in the anterior salivary gland of Drosophila.

Successful expression of genes transferred into distantly related species in which genetic functions have been maintained through evolution has been reported previously. In the case of the silkmoth Bombyx mori and the fruitfly Drosophila melanogaster, both of which produce chorions (eggshells), Bombyx chorion genes are correctly expressed in Drosophila despite their estimated 240-Myr phylogenetic divergence. Here we report that, although Drosophila does not produce silk, mechanisms regulating transcription have been conserved between the salivary gland of the fruitfly and the silk gland of the silkmoth larva.

Amino Acid Sequence↗
PubMed1993

Linear chromosomal physical and genetic map of Borrelia burgdorferi, the Lyme disease agent.

A physical map of the 952 kbp chromosome of Borrelia burgdorferi Sh-2-82 has been constructed. Eighty-three intervals on the chromosome, defined by the cleavage sites of 15 restriction enzymes, are delineated. The intervals vary in size from 96 kbp to a few hundred bp, with an average size of 11.5 kbp. A striking feature of the map is its linearity; no other bacterial groups are known to have linear chromosomes. The two ends of the chromosome do not hybridize with one another, indicating that there are no large common terminal regions. The chromosome of this strain was found to be stable in culture; passage 6, 165 and 320 cultures have identical chromosomal restriction maps. We have positioned all previously known Borrelia burgdorferi chromosomal genes and several newly identified ones on this map. These include the gyrA/gyrB/dnaA/dnaN gene cluster, the rRNA gene cluster, fla, flgE, groEL (hsp60), recA, the rho/hip cluster, the dnaK (hsp70)/dnaJ/grpE cluster, the pheT/pheS cluster, and the genes which encode the potent immunogen proteins p22A, p39 and p83. Our electrophoretic analysis detects five linear and at least two circular plasmids in B. burgdorferi Sh-2-82. We have constructed a physical map of the 53 kbp linear plasmid and located the operon that encodes the two major outer surface proteins ospA and ospB on this plasmid. Because of the absence of functional genetic tools for this organism, these maps will serve as a basis for future mapping, cloning and sequencing studies of B. burgdorferi.

Blotting, Southern↗
PubMed1991

Nucleotide sequence of the Escherichia coli recJ chromosomal region and construction of recJ-overexpression plasmids.

The nucleotide sequence of the recJ gene of Escherichia coli K-12 and two upstream coding regions was determined. Three regions were identified within these two upstream genes that exhibited weak to moderate promoter activity in fusions to the galK gene and are candidates for the recJ promoter. recJ appeared to be poorly translated: the recJ nucleotide sequence revealed a suboptimal initiation codon GUG, no discernible ribosome-binding consensus sequence, and relatively nonbiased synonymous codon usage. Comparison of the sequence of this region of the chromosome with DNA data bases identified the gene immediately downstream of recJ as prfB, which encodes translational release factor 2 and has been mapped near recJ at 62 min. No significant homology between recJ and other previously sequenced regions of DNA was detected. However, protein sequence comparisons with a gene upstream of recJ, denoted xprB, revealed significant homology with several site-specific recombination proteins. Its genetic function is presently unknown. Knowledge of the nucleotide sequence of recJ allowed the construction of a plasmid from which overexpression of RecJ protein could be induced. Supporting the notion that translation of recJ is limiting, a strong T7 bacteriophage promoter upstream of recJ did not, by itself, allow high-level expression of RecJ protein. The addition of a ribosome-binding sequence fused to the initiator GTG of recJ in this construction was necessary to promote expression of high levels of RecJ protein.

Amino Acid Sequence↗
PubMed2003

Motor dysfunction in type 5 adenylyl cyclase-null mice.

Various neurotransmitters, such as dopamine, stimulate adenylyl cyclase to produce cAMP, which regulates neuronal functions. Genetic disruption of the type 5 adenylyl cyclase isoform led to a major loss of adenylyl cyclase activity in a striatum-specific manner with a small increase in the expression of a few other adenylyl cyclase isoforms. D1 dopaminergic agonist-stimulated adenylyl cyclase activity was attenuated, and this was accompanied by a decrease in the expression of the D1 dopaminergic receptor and G(s)alpha. D2 dopaminergic agonist-mediated inhibition of adenylyl cyclase activity was also blunted. Type 5 adenylyl cyclase-null mice exhibited Parkinsonian-like motor dysfunction, i.e. abnormal coordination and bradykinesia detected by Rotarod and pole test, respectively, and to a lesser extent locomotor impairment was detected by open field tests. Selective D1 or D2 dopaminergic stimulation improved some of these disorders in this mouse model, suggesting the partial compensation of each dopaminergic receptor signal through the stimulation of remnant adenylyl cyclase isoforms. These findings extend our knowledge of the role of an effector enzyme isoform in regulating receptor signaling and neuronal functions and imply that this isoform provides a site of convergence of both D1 and D2 dopaminergic signals and balances various motor functions.

Adenylyl Cyclases↗
PubMed1991

Association of major histocompatibility complex class III complement components C2, BF, and C4 with Brazilian paracoccidioidomycosis.

A genetic influence of the major histocompatibility complex (MHC) on the susceptibility and the development of the different clinical forms of paracoccidioidomycosis (PCM) has been postulated. In the present investigation allotypes of MHC-coded class III gene products (complement components C2, BF, C4A, and B) were determined in 69 Brazilian PCM patients and 225 healthy control individuals matched for ethnic and geographic origin. The frequency of the non-expressed C4B allele (C4B*Q0) was significantly elevated in comparison to the controls (p less than 0.01; Fisher's exact test). Three out of 69 patients had a complete C4B deficiency as against 2 among 223 control individuals. The C4A*Q0 allele was also more frequent in the patients. Other C4 alleles were not seen to differ between the two groups. The analysis of BF allotypes showed a non-significant predominance of the rarer allele BF*S07 in the patients, whereas no difference in the distribution of C2 alleles was seen. The data on MHC class III association may support the hypothesis of immune response modulation in PCM and suggest a functional genetic role of complement action against the fungus and in the outcome of PCM infection. We conclude that MHC class III products, especially C4B*Q0, are associated with chronic uni- or multifocal PCM and may influence the course of the infection.

Adolescent↗
PubMed2001

A COL1A1 Sp1 binding site polymorphism predisposes to osteoporotic fracture by affecting bone density and quality.

Osteoporosis is a common disease with a strong genetic component. We previously described a polymorphic Sp1 binding site in the COL1A1 gene that has been associated with osteoporosis in several populations. Here we explore the molecular mechanisms underlying this association. A meta-analysis showed significant associations between COL1A1 "s" alleles and bone mineral density (BMD), body mass index (BMI), and osteoporotic fractures. The association with fracture was stronger than expected on the basis of the observed differences in BMD and BMI, suggesting an additional effect on bone strength. Gel shift assays showed increased binding affinity of the "s" allele for Sp1 protein, and primary RNA transcripts derived from the "s" allele were approximately three times more abundant than "S" allele--derived transcripts in "Ss" heterozygotes. Collagen produced from osteoblasts cultured from "Ss" heterozygotes had an increased ratio of alpha 1(I) protein relative to alpha 2(I), and this was accompanied by an increased ratio of COL1A1 mRNA relative to COL1A2. Finally, the yield strength of bone derived from "Ss" individuals was reduced when compared with bone derived from "SS" subjects. We conclude that the COL1A1 Sp1 polymorphism is a functional genetic variant that predisposes to osteoporosis by complex mechanisms involving changes in bone mass and bone quality.

Aged↗