References of "Balling, Rudi 50000566"
     in
Bookmark and Share    
Peer Reviewed
See detailProgressive loss of PAX9 expression correlates with increasing malignancy of dysplastic and cancerous epithelium of the human oesophagus.
Gerber, Josef-Karl; Richter, Thomas; Kremmer, Elisabeth et al

in Journal of Pathology (2002), 197(3), 293-7

Pax genes encode a family of transcription factors that play key roles in embryonic development. Whereas the functions of Pax genes in the adult organism are largely unknown, upregulated Pax gene ... [more ▼]

Pax genes encode a family of transcription factors that play key roles in embryonic development. Whereas the functions of Pax genes in the adult organism are largely unknown, upregulated Pax gene expression has been implicated in tumourigenesis. In this study, PAX9-specific monoclonal antibodies have been generated and it has been shown that PAX9 protein is expressed in the normal epithelium of the adult human oesophagus. PAX9 expression was either lost or significantly reduced in the majority of invasive carcinomas and epithelial dysplasias, the latter representing precancerous lesions. Notably, the percentage of PAX9-positive cells within the epithelium decreased with increasing malignancy of the epithelial lesion. These results identify PAX9 as a sensitive marker for deregulated differentiation of oesophageal keratinocytes and indicate a role for PAX9 in the normal differentiation process of internal stratified squamous epithelia. These data suggest that upregulated PAX9 expression is not required for the formation of the majority of squamous cell carcinomas of the human oesophagus. [less ▲]

Detailed reference viewed: 113 (1 UL)
Peer Reviewed
See detailIn situ gene expression analysis during BMP2-induced ectopic bone formation in mice shows simultaneous endochondral and intramembranous ossification.
Stoeger, Tobias; Proetzel, Gabriele E.; Welzel, Heike et al

in Growth Factors (2002), 20(4), 197-210

We examined the molecular progression of ectopic bone development upon application of recombinant human bone morphogenetic protein-2 (rhBMP2), using a commercial collagen type I carrier, in the hind ... [more ▼]

We examined the molecular progression of ectopic bone development upon application of recombinant human bone morphogenetic protein-2 (rhBMP2), using a commercial collagen type I carrier, in the hind quarter muscles of mice. We performed a gene expression study using mRNA in situ hybridisation to compare embryonic cartilage and bone formation with BMP2-induced ectopic bone formation. As bone growth can be induced postnatally or in adult animals, we examined the expression of molecules regulating embryonic bone development. We found that the mRNAs of the same molecules, such as Indian hedgehog (IHH), parathyroid hormone (PTH)/PTH-related peptide receptor (PPR) and BMPs, that regulate embryonic cartilage and bone development, are expressed during BMP-induced ectopic bone formation, suggesting parallels in the mechanisms controlling these processes. Our studies support by molecular means the previous findings in rats that BMP2-induced ectopic bone formation in mice undergoes bone development involving both modes, endochondral and intramembranous ossification, simultaneously at different sites of the implant. [less ▲]

Detailed reference viewed: 126 (2 UL)
Peer Reviewed
See detailRespiratory mechanics in mice: strain and sex specific differences.
Schulz, H.; Johner, C.; Eder, G. et al

in Acta Physiologica Scandinavica (2002), 174(4), 367-75

To assess the contribution of genetic background to respiratory mechanics, we developed a ventilator unit to measure lung function parameters in the mouse. We studied two commonly used inbred mice strains ... [more ▼]

To assess the contribution of genetic background to respiratory mechanics, we developed a ventilator unit to measure lung function parameters in the mouse. We studied two commonly used inbred mice strains originating from Mus musculus domesticus (C57BL/6 and C3HeB/FeJ) and a third strain derived from Mus musculus molossinus [Japanese fancy mouse 1 (JF1)]. The ventilator allows for accurate performance of the different breathing manoeuvres required for measuring in- and expiratory reserve capacity, quasi-static and dynamic compliance, and airway resistance. In combination with a mass spectrometer for monitoring gas concentrations, single-breath manoeuvres were performed and He-expirograms obtained, from which dead space volume and slope of phase III were determined. From each strain and each sex, 10, 2-month old animals were studied immediately after being killed by an intraperitoneal overdose of xylazine and ketamine. C3HeB/FeJ and C57BL/6 exhibited comparable lung volumes. In male C3HeB/FeJ mice, e.g. vital capacity (VC) was 1072 +/- 79 microL, inspiratory reserve capacity 782 +/- 88 microL, and dead space volume at total lung inflation 216 +/- 18 microL. Lung volumes of JF1 were significantly lower (e.g. VC 611 +/- 53 microL, P < 0.01) even when normalized to body weight. In all three strains, specific lung volumes were significantly higher in females than in males, possibly explained by a higher oxygen demand during pregnancy and lactation, both of which fill most of their life times. Static compliance in C3HeB/FeJ was 64.3 +/- 5.4 microL cmH2O-1. It was smaller in C57BL/6 and JF1 mice, even when related to the lung volume. Analysis of the degree of genetic vs. non-genetic components of the phenotypic variation revealed that at least 80% of the total variation of lung volumes and static compliance in the mixed population is attributable to genetic differences between individuals. These differences will be verified in further studies by segregation and genetic linkage analysis. [less ▲]

Detailed reference viewed: 156 (0 UL)
Peer Reviewed
See detailConditional inactivation of Sox9: a mouse model for campomelic dysplasia.
Kist, Ralf; Schrewe, Heinrich; Balling, Rudi UL et al

in Genesis (2002), 32(2), 121-3

Detailed reference viewed: 148 (3 UL)
Peer Reviewed
See detailBeethoven, a mouse model for dominant, progressive hearing loss DFNA36.
Vreugde, Sarah; Erven, Alexandra; Kros, Corne J. et al

in Nature Genetics (2002), 30(3), 257-8

Despite recent progress in identifying genes underlying deafness, there are still relatively few mouse models of specific forms of human deafness. Here we describe the phenotype of the Beethoven (Bth ... [more ▼]

Despite recent progress in identifying genes underlying deafness, there are still relatively few mouse models of specific forms of human deafness. Here we describe the phenotype of the Beethoven (Bth) mouse mutant and a missense mutation in Tmc1 (transmembrane cochlear-expressed gene 1). Progressive hearing loss (DFNA36) and profound congenital deafness (DFNB7/B11) are caused by dominant and recessive mutations of the human ortholog, TMC1 (ref. 1), for which Bth and deafness (dn) are mouse models, respectively. [less ▲]

Detailed reference viewed: 150 (0 UL)
Peer Reviewed
See detailHydrogen peroxide-mediated killing of Caenorhabditis elegans by Streptococcus pyogenes.
Jansen, W. T. M.; Bolm, M.; Balling, Rudi UL et al

in Infection and Immunity (2002), 70(9), 5202-7

Caenorhabditis elegans is currently introduced as a new, facile, and cheap model organism to study the pathogenesis of gram-negative bacteria such as Pseudomonas aeruginosa and Salmonella enterica serovar ... [more ▼]

Caenorhabditis elegans is currently introduced as a new, facile, and cheap model organism to study the pathogenesis of gram-negative bacteria such as Pseudomonas aeruginosa and Salmonella enterica serovar Typhimurium. The mechanisms of killing involve either diffusible exotoxins or infection-like processes. Recently, it was shown that also some gram-positive bacteria kill C. elegans, although the precise mechanisms of killing remained open. We examined C. elegans as a pathogenesis model for the gram-positive bacterium Streptococcus pyogenes, a major human pathogen capable of causing a wide spectrum of diseases. We demonstrate that S. pyogenes kills C. elegans, both on solid and in liquid medium. Unlike P. aeruginosa and S. enterica serovar Typhimurium, the killing by S. pyogenes is solely mediated by hydrogen peroxide. Killing required live streptococci; the killing capacity depends on the amount of hydrogen peroxide produced, and killing can be inhibited by catalase. Major exotoxins of S. pyogenes are not involved in the killing process as confirmed by using specific toxin inhibitors and knockout mutants. Moreover, no accumulation of S. pyogenes in C. elegans is observed, which excludes the involvement of infection-like processes. Preliminary results show that S. pneumoniae can also kill C. elegans by hydrogen peroxide production. Hydrogen peroxide-mediated killing might represent a common mechanism by which gram-positive, catalase-negative pathogens kill C. elegans. [less ▲]

Detailed reference viewed: 121 (0 UL)
Peer Reviewed
See detailThe Notch ligand Jagged1 is required for inner ear sensory development.
Kiernan, A. E.; Ahituv, N.; Fuchs, H. et al

in Proceedings of the National Academy of Sciences of the United States of America (2001), 98(7), 3873-8

Within the mammalian inner ear there are six separate sensory regions that subserve the functions of hearing and balance, although how these sensory regions become specified remains unknown. Each sensory ... [more ▼]

Within the mammalian inner ear there are six separate sensory regions that subserve the functions of hearing and balance, although how these sensory regions become specified remains unknown. Each sensory region is populated by two cell types, the mechanosensory hair cell and the supporting cell, which are arranged in a mosaic in which each hair cell is surrounded by supporting cells. The proposed mechanism for creating the sensory mosaic is lateral inhibition mediated by the Notch signaling pathway. However, one of the Notch ligands, Jagged1 (Jag1), does not show an expression pattern wholly consistent with a role in lateral inhibition, as it marks the sensory patches from very early in their development--presumably long before cells make their final fate decisions. It has been proposed that Jag1 has a role in specifying sensory versus nonsensory epithelium within the ear [Adam, J., Myat, A., Roux, I. L., Eddison, M., Henrique, D., Ish-Horowicz, D. & Lewis, J. (1998) Development (Cambridge, U.K.) 125, 4645--4654]. Here we provide experimental evidence that Notch signaling may be involved in specifying sensory regions by showing that a dominant mouse mutant headturner (Htu) contains a missense mutation in the Jag1 gene and displays missing posterior and sometimes anterior ampullae, structures that house the sensory cristae. Htu/+ mutants also demonstrate a significant reduction in the numbers of outer hair cells in the organ of Corti. Because lateral inhibition mediated by Notch predicts that disruptions in this pathway would lead to an increase in hair cells, we believe these data indicate an earlier role for Notch within the inner ear. [less ▲]

Detailed reference viewed: 118 (0 UL)
Peer Reviewed
See detailEthylnitrosourea-induced mutation in mice leads to the expression of a novel protein in the eye and to dominant cataracts.
Graw, J.; Klopp, N.; Loster, J. et al

in Genetics (2001), 157(3), 1313-20

A novel ENU-induced mutation in the mouse leading to a nuclear and zonular opacity of the eye lens (Aey1) was mapped to chromosome 1 between the markers D1Mit303 and D1Mit332. On the basis of the ... [more ▼]

A novel ENU-induced mutation in the mouse leading to a nuclear and zonular opacity of the eye lens (Aey1) was mapped to chromosome 1 between the markers D1Mit303 and D1Mit332. On the basis of the chromosomal position, the gamma-crystallin encoding gene cluster (Cryg) and the betaA2-crystallin encoding gene Cryba2 were tested as candidate genes. An A --> T mutation destroys the start codon of the Cryge gene in the mutants; this mutation was confirmed by the absence of a restriction site for NcoI in the corresponding genomic fragment of homozygous mutants. The next in-frame start codon is 129 bp downstream; this predicted truncated gammaE-crystallin consists of 131 amino acids, resulting in a molecular mass of 14 kD. However, another open reading frame was observed just 19 bp downstream of the regular Cryge start codon, resulting in a protein of 119 amino acids and a calculated molecular weight of 13 kD. Western blot analysis using polyclonal antibodies against gamma-crystallins or the novel Aey1-specific protein demonstrated the specific expression of the Aey1 protein in the cataractous lenses only; the truncated form of the gammaE-crystallin could not be detected. Therefore, it is concluded that the novel protein destroys the sensitive cellular structure of the eye lens. [less ▲]

Detailed reference viewed: 65 (0 UL)
Peer Reviewed
See detailENU mutagenesis: analyzing gene function in mice.
Balling, Rudi UL

in Annual Review of Genomics & Human Genetics (2001), 2

With the completion of the human genome, sequence analysis of gene function will move into the center of future genome research. One of the key strategies for studying gene function involves the genetic ... [more ▼]

With the completion of the human genome, sequence analysis of gene function will move into the center of future genome research. One of the key strategies for studying gene function involves the genetic dissection of biological processes in animal models. Mouse mutants are of particular importance for the analysis of disease pathogenesis and transgenic techniques, and gene targeting have become routine tools. Recently, phenotype-driven strategies using chemical mutagenesis have been the target of increasing interest. In this review, the current state of ENU mutagenesis and its application as a systematic tool of genome analysis are examined. [less ▲]

Detailed reference viewed: 112 (0 UL)
Peer Reviewed
See detailSequence interpretation. Functional annotation of mouse genome sequences.
Nadeau, J. H.; Balling, Rudi UL; Barsh, G. et al

in Science (2001), 291(5507), 1251-5

Detailed reference viewed: 138 (7 UL)
Peer Reviewed
See detailCharacterization of a mutation in the lens-specific MP70 encoding gene of the mouse leading to a dominant cataract.
Graw, J.; Loster, J.; Soewarto, D. et al

in Experimental Eye Research (2001), 73(6), 867-76

During an ethylnitrosourea mutagenesis screen, Aey5, a new mouse mutation exhibiting an autosomal dominant congenital cataract was isolated. The cataractous phenotype is visible at the eye opening and ... [more ▼]

During an ethylnitrosourea mutagenesis screen, Aey5, a new mouse mutation exhibiting an autosomal dominant congenital cataract was isolated. The cataractous phenotype is visible at the eye opening and progresses to a nuclear and zonular cataract at 2 months of age with no difference in onset or severity between heterozygous and homozygous mutants. Histological analysis revealed that fiber cell differentiation continues at the lens bow region, but the cell nuclei do not degrade normally and remain in the deeper cortex. Further, the lens nucleus has clefts of various sizes while the remainder of the eye was morphologically normal. The mutation was mapped to chromosome 3 between the markers D3Mit101 and D3Mit77 near the connexin encoding genes Gja5 and Gja8. Sequence analysis revealed no differences in the Gja5 gene, but identified a T-->C mutation at position 191 in the Gja8 gene, which was confirmed by an additional Mva 12691 restriction site in the genomic DNA of homozygous mutants. This mutation results in Val-->Ala substitution at codon 64 of connexin50 (Cx50) also known as lens membrane protein 70 (MP70). Aey5 represents the second dominant mouse cataract mutant affecting Cx50, a membrane protein preferentially expressed in the lens. Since both mutations affect similar regions in the first extracellular domain this region appears to be critically important for its function in lens transparency. [less ▲]

Detailed reference viewed: 104 (0 UL)
Peer Reviewed
See detailSystematic approaches to mouse mutagenesis.
Brown, S. D.; Balling, Rudi UL

in Current Opinion in Genetics and Development (2001), 11(3), 268-73

A major challenge in post-genomics is the systematic determination of mammalian gene function. A variety of mouse mutagenesis technologies, both gene- and phenotype-driven, are being used to underpin ... [more ▼]

A major challenge in post-genomics is the systematic determination of mammalian gene function. A variety of mouse mutagenesis technologies, both gene- and phenotype-driven, are being used to underpin systematic and comprehensive approaches to mammalian gene function studies. Recently, a number of centres have completed large-scale ENU mutagenesis programmes that employ a phenotype-driven approach to the generation of mouse mutants. The use of ENU mutagenesis represents a powerful and efficient approach to mammalian gene-function studies, but many parallel developments are needed in downstream technologies to properly harness the new enlarged mouse-mutant resources that are being created. [less ▲]

Detailed reference viewed: 96 (1 UL)
Peer Reviewed
See detailEnu mouse mutagenesis: generation of mouse mutants with aberrant plasma IgE levels.
Alessandrini, F.; Jakob, T.; Wolf, A. et al

in International Archives of Allergy and Applied Immunology (2001), 124(1-3), 25-8

BACKGROUND: The ENU Mouse Mutagenesis Project aims at a large-scale, systematic production of mouse mutants using the alkylating agent ethyl-nitrosourea (ENU). Offspring of mutagenized mice are subjected ... [more ▼]

BACKGROUND: The ENU Mouse Mutagenesis Project aims at a large-scale, systematic production of mouse mutants using the alkylating agent ethyl-nitrosourea (ENU). Offspring of mutagenized mice are subjected to a multiparameter screen to detect alterations in various phenotypes with the ultimate goal of identifying novel genes relevant for the expression of the phenotype. Using this approach, we have analyzed plasma IgE concentrations to identify mouse mutants with aberrant plasma IgE levels. METHODS AND RESULTS: ENU-mutagenized male C3HeB/FeJ were mated to wild-type females to produce F1 offspring. F1 animals were analyzed for alterations in their plasma IgE concentrations that showed a dominant mode of inheritance, or bred further to screen for recessive phenotypes. Plasma IgE concentrations were determined by ELISA and a normal range for plasma IgE was established using C3HeB/FeJ wild-type animals. So far we have tested 6568 F1 animals. Repeated testing confirmed a stable aberrant IgE phenotype in 124 animals. To confirm the genetic basis of the observed phenotype, these mice were subjected to confirmation crossing. Currently we have established 9 independent mutant mouse lines (3 with high plasma IgE and 6 with plasma IgE below detection limit) that have been genetically confirmed and additional 24 variant mouse lines are currently undergoing confirmation testing. CONCLUSION: ENU mouse mutagenesis allowed us to generate and identify mouse mutants with aberrant plasma IgE levels, which may be used to characterize novel genes involved in IgE regulation and may serve as animal models for IgE-mediated diseases. [less ▲]

Detailed reference viewed: 134 (2 UL)
Peer Reviewed
See detailCharacterization of a new, dominant V124E mutation in the mouse alphaA-crystallin-encoding gene.
Graw, J.; Loster, J.; Soewarto, D. et al

in Investigative Ophthalmology and Visual Science (2001), 42(12), 2909-15

PURPOSE: During an ethylnitrosourea (ENU) mutagenesis screening, mice were tested for the occurrence of dominant cataracts. The purpose of the study was morphologic description, mapping of the mutant gene ... [more ▼]

PURPOSE: During an ethylnitrosourea (ENU) mutagenesis screening, mice were tested for the occurrence of dominant cataracts. The purpose of the study was morphologic description, mapping of the mutant gene, and characterization of the underlying molecular lesion in a particular mutant, Aey7. METHODS: Isolated lenses were photographed and histologic sections of the eye were analyzed according to standard procedures. Linkage analysis was performed with a set of microsatellite markers covering all autosomal chromosomes. cDNA was amplified after reverse transcription of lens mRNA. For PCR, cDNA or genomic DNA was used as a template. RESULTS: Nuclear opacity and posterior suture anomaly were visible at eye opening and progressed to a nuclear and zonular cataract at 2 months of age. The opacity as well as the microphthalmia was more pronounced in the homozygotes than in the heterozygotes. The mutation was mapped to chromosome 17 between the markers D17Mit133 and D17Mit180. This position made the alphaA-crystallin-encoding gene (Cryaa) an excellent candidate gene. Sequence analysis revealed a mutation of a T to an A at position 371 in the Cryaa cDNA. The mutation was confirmed by an additional MnlI restriction site in the genomic DNA of homozygous mutants leading to replacement of Val with Glu at codon 124 affecting the C-terminal region of the alphaA-crystallin. CONCLUSIONS: The Aey7 mutant represents the first dominant mouse cataract mutation affecting the Cryaa gene. The mutation leads to progressive opacification of the lens. Compared with the beta- and gamma-crystallin-encoding genes, mutations in the alpha-crystallin-encoding genes are rare. [less ▲]

Detailed reference viewed: 63 (2 UL)
Peer Reviewed
See detailAey2, a new mutation in the betaB2-crystallin-encoding gene of the mouse.
Graw, J.; Loster, J.; Soewarto, D. et al

in Investigative Ophthalmology and Visual Science (2001), 42(7), 1574-80

PURPOSE: During an ethylnitrosourea (ENU) mutagenesis screen, mice were tested for the occurrence of dominant cataracts. One particular mutant was found that caused progressive opacity and was referred to ... [more ▼]

PURPOSE: During an ethylnitrosourea (ENU) mutagenesis screen, mice were tested for the occurrence of dominant cataracts. One particular mutant was found that caused progressive opacity and was referred to as Aey2. The purpose of the study was to provide a morphologic description, to map the mutant gene, and to characterize the underlying molecular lesion. METHODS: Isolated lenses were photographed, and histologic sections of the eye were analyzed according to standard procedures. Linkage analysis was performed using a set of microsatellite markers covering all autosomal chromosomes. cDNA from candidate genes was amplified after reverse transcription of lens mRNA. RESULTS: The cortical opacification visible at eye opening progressed to an anterior suture cataract and reached its final phenotype as total opacity at 8 weeks of age. There was no obvious difference between heterozygous and homozygous mutants. The mutation was mapped to chromosome 5 proximal to the marker D5Mit138 (8.7 +/- 4.2 centimorgan [cM]) and distal to D5Mit15 (12.8 +/- 5.4 cM). No recombinations were observed to the markers D5Mit10 and D5Mit25. This position makes the genes within the betaA4/betaB-crystallin gene cluster excellent candidate genes. Sequence analysis revealed a mutation of T-->A at position 553 in the Crybb2 gene, leading to an exchange of Val for GLU: It affects the same region of the Crybb2 gene as in the Philly mouse. Correspondingly, the loss of the fourth Greek key motif is to be expected. CONCLUSIONS: The Aey2 mutant represents the second allele of Crybb2 in mice. Because an increasing number of beta- and gamma-crystallin mutations have been reported, a detailed phenotype-genotype correlation will allow a clearer functional understanding of beta- and gamma-crystallins. [less ▲]

Detailed reference viewed: 73 (1 UL)
Peer Reviewed
See detailComparative analysis of the genomic organization of Pax9 and its conserved physical association with Nkx2-9 in the human, mouse, and pufferfish genomes.
Santagati, F.; Gerber, J. K.; Blusch, J. H. et al

in Mammalian Genome (2001), 12(3), 232-7

As a first step towards the identification of cis-regulatory elements of Pax9 by means of comparative genomics, we have analyzed genome regions encompassing the Pax9 gene in three vertebrate species ... [more ▼]

As a first step towards the identification of cis-regulatory elements of Pax9 by means of comparative genomics, we have analyzed genome regions encompassing the Pax9 gene in three vertebrate species, humans, mice (Mus musculus), and the Japanese pufferfish (Fugu rubripes). We show the genomic organization of Pax9 and its physical association with Nkx2-9 conserved in the three species. We discuss about possible implications of the conserved synteny between Pax9 and Nkx2-9 in a context of vertebrate evolution. This report also includes the first description of the primary structures of Fugu Pax9 and Nkx2-9. Furthermore, we report the identification of a novel upstream exon and putative transcription start sites in mouse Pax9. Our results suggest that transcription of Pax9 may be initiated at two alternative start sites and driven by TATA-less promoters. [less ▲]

Detailed reference viewed: 112 (1 UL)
Peer Reviewed
See detailThe battle of two genomes: genetics of bacterial host/pathogen interactions in mice.
Lengeling, A.; Pfeffer, K.; Balling, Rudi UL

in Mammalian Genome (2001), 12(4), 261-71

Genetic factors strongly determine the outcome of infectious diseases caused by various pathogens. The molecular mechanisms of resistance and susceptibility in humans, however, remains largely unknown ... [more ▼]

Genetic factors strongly determine the outcome of infectious diseases caused by various pathogens. The molecular mechanisms of resistance and susceptibility in humans, however, remains largely unknown. Complex interactions of multiple genes that control the host response to a pathogen further complicate the picture. Animal models have a tremendous potential to dissect the complex genetic system of host-pathogen interaction into single components. This is particularly true for the mouse, which will continue to develop into an invaluable tool in the identification and cloning of host resistance genes. Three main approaches have been taken to establish mouse models for human infectious diseases: 1) Production of mouse mutants by gene targeting; 2) positional cloning of host-resistance genes in mutant mice; and 3) mapping and characterization of quantitative trait loci (QTL) controlling the complex aspects of host-pathogen interactions. The contribution of all three methods to the understanding of infectious diseases in humans will be reviewed in this work, with a special emphasis on the studies of resistance/susceptibility mechanism in bacterial infections. [less ▲]

Detailed reference viewed: 101 (1 UL)
Peer Reviewed
See detailFrom developmental biology to developmental toxicology.
Balling, Rudi UL; Hrabe de Angelis, M.

in Annals of the New York Academy of Sciences (2000), 919

Progress derived from the human genome project will have tremendous impact on toxicology. Questions concerning genetic susceptibility or resistance to toxic compound exposure and the dissection of the ... [more ▼]

Progress derived from the human genome project will have tremendous impact on toxicology. Questions concerning genetic susceptibility or resistance to toxic compound exposure and the dissection of the molecular mechanisms involved will be at the forefront of future toxicological research. In recent years, it was recognized that many of the molecular control mechanisms of embryogenesis have been conserved during evolution. The relevance of these observations for toxicology and the application of genetic approaches using mouse mutants as a tool for functional genome analysis are discussed. [less ▲]

Detailed reference viewed: 125 (3 UL)
Peer Reviewed
See detailThe biochemical metabolite screen in the Munich ENU Mouse Mutagenesis Project: determination of amino acids and acylcarnitines by tandem mass spectrometry.
Rolinski, B.; Arnecke, R.; Dame, T. et al

in Mammalian Genome (2000), 11(7), 547-51

BACKGROUND: Gene mutations often result in altered protein expression and, in turn, lead to changes in metabolite levels in one or more distinct biochemical pathways. Traditional analytical methods for ... [more ▼]

BACKGROUND: Gene mutations often result in altered protein expression and, in turn, lead to changes in metabolite levels in one or more distinct biochemical pathways. Traditional analytical methods for metabolite determination are usually time consuming, expensive, and, thus, not suitable for high throughput analysis. However, recent developments in electrospray-tandem-mass-spectrometry allow comprehensive metabolite scanning from very small amounts of blood with high speed, cost effectiveness, and accuracy. METHODS: A blood spot from a filter paper equivalent to 3 microl of blood was punched out and transferred to a 96-well microtiter plate. After addition of a set of 14 stable isotope-labeled internal standards, amino acids and acylcarnitines were extracted with methanol. The dried residue was derivatized with butanolic hydrochloric acid and subjected to MSMS analysis. RESULTS: Acyl-carnitines were all determined by a precursor ion scan of 85 Da. Neutral loss scanning of 102 Da was suitable for the quantitation of threonine, serine, proline, histidine, alanine, aspartic acid, glutamic acid, methionine, tyrosine, phenylalanine, isoleucine/leucine and valine. Glycine was detected by a loss of a 56-Da fragment, whereas a 119-Da loss was suitable for the measurement of citrulline, ornithine, arginine, and lysine. Specific problems encountered: owing to their identical molecular weight, isoleucine and leucine could not be quantitated separately, and, owing to their instability, glutamine and asparagine were found to be decarboxylated to their respective acids. Determination was linear over the concentration range tested (20 to 1000 micromol/L), and intraassay and interassay coefficients of variation were in the range of 10-15%. CONCLUSION: ESI-MSMS proved to be a highly sensitive, linear, and sufficiently precise method for the quantitative determination of amino acids and acylcarnitines in mouse blood, allowing large-scale screening applications when speed and cost effectiveness are mandatory. [less ▲]

Detailed reference viewed: 142 (1 UL)
Peer Reviewed
See detailThe clinical-chemical screen in the Munich ENU Mouse Mutagenesis Project: screening for clinically relevant phenotypes.
Rathkolb, B.; Decker, T.; Fuchs, E. et al

in Mammalian Genome (2000), 11(7), 543-6

Detailed reference viewed: 151 (1 UL)