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R Jaussi

Publications and source records attributed to R Jaussi.

At least 19 recordsLinked to original sources
PubMed2006

[Isolated neurofibromatosis of the urinary bladder. A rare cause of recurrent cystitis].

Neurofibromas of the urinary bladder occur as isolated phenomena or as part of generalized neurofibromatosis or von Recklinghausen's disease. This benign mesenchymal tumor can be the cause of subvesical obstruction, hematuria or chronic cystitis. The lesion is rare. Our case of isolated extended neurofibromatosis of the urinary bladder was diagnosed in a 19-year-old girl with an 8-year history of chronic cystitis. Two transurethral resections were successful in relieving symptoms. Possible further therapy was delayed because of the patient's desire for children.

Adult↗
PubMed2005

[Testicular torsion in testicular duplication. Kasuistik und Literaturubersicht].

We describe a case of testicular duplication presenting as torsion of the supernumerary distal testis in a 14-year-old boy. Clinical examination showed an unclear mass above the left testis; intraoperatively, the supernumerary testis was linked to the regular testis by a common epididymis and shared a common vas with it. The distal testis was resected due to severe hemorrhagic damage. This condition represents the result of transversal division of the wolffian duct during organogenesis. Review of the literature revealed that testicular torsion, testicular tumor, unclear scrotal masses, or continuing potentia generandi after bilateral vasectomy were the reasons that polyorchidism was detected.

Adolescent↗
PubMed2001

Signalling properties of an HIV-encoded angiogenic peptide mimicking vascular endothelial growth factor activity.

HIV-1 expresses a multifunctional protein called TAT (trans-acting transcriptional activator), the function of which in vivo is tightly correlated with the incidence of Kaposi's sarcoma in AIDS patients. TAT is angiogenic and apparently binds to receptors specific for vascular endothelial growth factor (VEGF). Amino acids 46-60 of HIV-TAT, known as the basic peptide, have been shown to be responsible for its functional interaction with VEGF receptors. To characterize further the binding properties of this peptide, its coding sequence was fused to the reading frame of bacterial thioredoxin, allowing the production of large amounts of chimaeric polypeptides in bacteria in a biologically active form. Binding of chimaeric proteins to VEGF receptors was studied in vitro in endothelial cell cultures expressing either of the two receptors. Chimaeric thioredoxin proteins carrying the basic domain of TAT bound to both VEGF receptors with affinities similar to those of HIV-TAT or VEGF. Interestingly, these polypeptides competed only partially with VEGF for receptor binding, implying different binding sites for the TAT peptide and VEGF. This suggests that TAT binds VEGF receptors at new sites that might be useful targets for pharmacological intervention during pathological angiogenesis. The thioredoxin/basic-peptide chimaeras are functional agonists that mediate VEGF receptor signalling: (1) they stimulate the growth of endothelial cells; (2) together with basic fibroblast growth factor they cause tube formation of endothelial cells in collagen gels; (3) they induce blood vessel formation on the chicken chorioallantoic membrane; and (4) they activate VEGF receptor kinase and mitogen-activated protein kinase activity.

Animals↗
PubMed2001

The long form of CDK2 arises via alternative splicing and forms an active protein kinase with cyclins A and E.

We have reinvestigated the long form of cyclin-dependent kinase (CDK)2 that is expressed in many rodent cells. We show that the mRNA encoding CDK2L arises by alternative splicing and that the encoded protein can bind to, and be activated by, cyclins A and E. The complex of CDK2L with cyclin A has about half the specific activity of the equivalent CDK2-cyclin A complex. Also, CDK2L--cyclin A is inhibited to the same extent and by the same concentrations of p21(CIP1) as CDK2--cyclin A. The nucleotide sequences of intron V in the human and murine CDK2 genes, where the sequences encoding the 48-residue insert in CDK2L are located, show very high conservation in the position of the alternatively spliced exon and its surroundings. Despite this, we were not able to detect significant expression of CDK2L in human cell lines, although a low level is expressed in COS-1 cells from monkeys.

Alternative Splicing↗
PubMed2000

Detection of c-kit mutation Asp 816 to Val in microdissected bone marrow infiltrates in a case of systemic mastocytosis associated with chronic myelomonocytic leukaemia.

BACKGROUND/AIMS: The occurrence of myeloid leukaemia in patients with systemic mastocytosis is a well recognised phenomenon. However, the pathophysiological basis of such a coevolution has not been clarified. Recent data have shown that the c-kit mutation Asp 816 to Val is detectable in neoplastic mast cells in most patients with systemic mastocytosis, including those who have associated haematological disorders. The aim of this study was to study clonal disease evolution by analysing bone marrow cells from a patient with systemic mastocytosis and associated chronic myelomonocytic leukaemia (CMML) for the presence of this mutation. METHODS: The DNA of microdissected bone marrow cells from a patient with systemic mastocytosis and associated CMML was analysed for the presence of the c-kit mutation Asp 816 to Val by means of HinfI digestion and direct sequencing of semi-nested polymerase chain reaction (PCR) products. RESULTS: The two neoplasms could easily be identified and discriminated in paraffin wax embedded bone marrow sections by tryptase and chloroacetate esterase staining. A total number of 10 tryptase positive systemic mastocytosis infiltrates and 10 tryptase negative CMML infiltrates were removed by microdissection. As assessed by HinfI digestion and direct sequencing of semi-nested PCR products, the c-kit mutation Asp 816 to Val was detected in five of seven systemic mastocytosis infiltrates and four of six CMML infiltrates. By contrast, no c-kit mutation Asp 816 to Val was found in bone marrow infiltrates in patients with CMML without associated systemic mastocytosis (n = 20). CONCLUSION: These data support a monoclonal evolution of systemic mastocytosis and concurrent CMML in the patient studied.

Aged↗
PubMed1999

Anti-neuroblastoma antibody chCE7 binds to an isoform of L1-CAM present in renal carcinoma cells.

Immunoprecipitation after cell surface labeling of human neuroblastoma cells showed that the anti-neuroblastoma monoclonal antibody (mAb) chCE7 binds to a 200,000 M(r) cell surface protein. The protein was partially purified by immuno-affinity chromatography from a human renal carcinoma and a human neuroblastoma cell line, which both showed high levels of binding of MAb chCE7. NH(2)-terminal sequences of 18 and 15 amino acid residues were determined. Both sequences isolated from the renal carcinoma and the neuroblastoma cells showed strong homology to human cell adhesion molecule L1 (L1-CAM), and both were characterized by the NH(2)-terminal deletion of 5 amino acids, comprising exon 2 of L1-CAM. Reverse trancription-polymerase chain reaction (RT-PCR) analysis of the regions spanning exon 2 and exon 27 of L1-CAM indicated that in neuroblastoma cells both transcripts for the full-length and exon-deleted forms are present, whereas in the renal carcinoma cell lines only the exon-deleted L1-CAM isoform were detected. Western blot analysis showed that 6 of 7 tested renal carcinoma cell lines and 5 of 15 renal carcinoma tissues expressed L1-CAM. In normal adult kidney tissue, very low levels of protein expression were found. Northern blot analysis confirmed that in renal carcinoma and neuroblastoma cell lines L1-CAM mRNA levels are correlated with protein expression.

Animals↗
PubMed1999

Enzyme-linked immunosorbent assay for the measurement of JNK activity in cell extracts.

A colorimetric enzyme-linked immunosorbent assay (ELISA) for the measurement of kinase activity of c-Jun N-terminal kinases (JNKs) in cell extracts is described. The assay involves passive immobilisation of the substrate GST-cJun on the surface of a microtiter plate, selection of JNK protein kinases directly in substrate-coated wells, kinase reaction, and detection of substrate phosphorylation by a phosphoepitope-specific antibody. The ability of this assay to selectively measure JNK activity relies on the high-affinity interaction between JNKs and c-Jun. Accordingly, we found that JNKs could be captured on the microtiter plate surface through binding to the immobilised GST-cJun. Moreover, JNKs retained the specificity of their interaction with and phosphorylation of c-Jun with respect to the dependence on both intact docking domain and the dimerisation state of c-Jun. This novel procedure represents a marked improvement on conventional radioactive assays in terms of sensitivity, accuracy of evaluation, low time consumption, high throughput and amenability to automation. It is expected to be useful forthe acceleration and facilitation of JNK activity measurement in cell extracts, in particular for large-scale screening of clinical samples.

3T3 Cells↗
PubMed1999

Vascular endothelial growth factor (VEGF) and its receptors in tumor-bearing dogs.

The molecular biology of the angiogenic growth factor, vascular endothelial growth factor (VEGF), has been studied in the dog. All major isoforms of VEGF are present in the dog. The amino acid sequences are identical between human and dog in the loop regions that are responsible for receptor binding. Accordingly, the VEGF receptors of dogs and humans are very similar and permit functional exchange of the growth factor. Here we show that canine VEGF activates human endothelial cells to the same extent as human VEGF. Similarly, the two proteins display identical cell binding properties. The VEGF receptor 1 (Flt-1) shows the same alternative splicing in humans and dogs and is overexpressed in the majority of tumors in both species. VEGF occurs also in canine tumors in similar relative quantities as in human malignancies. Based on the literature and our study we suggest that the molecular biology and the function of the VEGF signaling system are virtually identical in humans and canines and in healthy as well as in disease conditions.

Alternative Splicing↗
PubMed1998

High-level expression of soluble heterologous proteins in the cytoplasm of Escherichia coli by fusion to the bacteriophage lambda head protein D.

The bacteriophage Lambda head protein D (gpD) is a small major capsid protein (110aa; 11.6kDa; pI=5.68, devoid of cysteine residues) that is essential for stable head morphogenesis. We found that a His-tagged derivative of gpD (gpHD) is a monomeric protein with efficient expression properties and high resistance towards thermally induced irreversible aggregation. In addition, gpHD can be used as a fusion partner for high-level expression of soluble heterologous proteins in the cytoplasm of Escherichia coli. Its broad utility is illustrated by the production of various mammalian proteins by fusion to its C-terminus. As a fusion partner, gpHD is thought to mediate optimal translation initiation while reducing inclusion body formation and protein degradation. In addition, it provides a His-tag for simple purification. gpHD may act as a 'cytoplasmic anchor' by keeping its unfolded fusion partner in solution, thereby providing more time for proper folding. An ever-increasing number of open reading frames (ORFs) are being identified in the various genome sequencing programs. gpHD has the potential to be harnessed for the development of highly efficient cytoplasmic expression systems that might contribute to the production and characterization of these novel polypeptides. Protein D is also an established fusion partner for phage display. It thus presents the attractive opportunity of coupling the selection of heterologous proteins from a phage library to their subsequent high-level expression.

Bacteriophage lambda↗
PubMed1996

Humoral and cell-mediated autoimmunity in allergy to Aspergillus fumigatus.

A cDNA encoding an allergenic protein was isolated from an Aspergillus fumigatus (A. fumigatus) cDNA library displayed on the surface of filamentous phage. Serum immunoglobulin E (IgE) from A. fumigatus-sensitized individuals was used to enrich phage-expressing gene products binding to IgE. One of the cDNAs encoded a 26.7-kD protein that was identified as a manganese superoxide dismutase (MnSOD) sharing 51.5% identity and 67.2% homology to the corresponding human enzyme. Both human and A. fumigatus MnSOD coding sequences were expressed in Escherichia coli as [His]6-tagged fusion proteins and purified by Ni(2+)-chelate affinity chromatography. The two recombinant MnSODs were both recognized by IgE antibodies from subjects allergic to the A. fumigatus MnSOD and elicited specific immediate type allergic skin reactions in these individuals. Moreover, both human and A. fumigatus MnSOD induced proliferation in peripheral blood mononuclear cells of A. fumigatus-allergic subjects who showed specific IgE responses and reacted in skin tests to MnSOD. These observations provide evidence for autoreactivity to the human MnSOD in allergic persons sensitized to an environmental allergen from A. fumigatus who share a high degree of sequence homology to the corresponding human enzyme.

Amino Acid Sequence↗
PubMed1995

Homologous nuclear-encoded mitochondrial and cytosolic isoproteins. A review of structure, biosynthesis and genes.

Mitochondrial and cytosolic proteins may be expected to differ in specific traits due to their different intracellular location. However, the identification of these differences between mitochondrial and cytosolic proteins is complicated by the heterogeneity of the two protein groups. These difficulties have been overcome by comparing traits of homologous genes, which are derived from a common ancestor gene, and their gene products. An earlier report [Hartmann, C., Christen, P. & Jaussi, R. (1991) Nature 352, 762-763] describing a positive net charge difference between the mature parts of nuclear-encoded mitochondrial proteins and their homologous cytosolic isoproteins, could be corroborated by extending the data collection. New data were gathered from computer databases and published studies. The average isoelectric points of the mitochondrial and cytosolic isoproteins are 7.5 and 6.5, respectively. Depending on the type of protein, the observed difference results from differences in the number of basic and/or acidic amino acid residues in the isoproteins. Probably both the conditions required for mitochondrial protein import and the local conditions within the organelle furthered the evolution of basic protein structures. The contribution of the mitochondrial targeting peptide to the positive charge of precursors of nuclear-encoded mitochondrial proteins is largest when the value of the isoelectric point of the mature protein is small. This mutual dependence of the charge of the targeting peptide and the mature protein part supports the notion that positive charge is essential for mitochondrial protein import. Several traits other than electric charge, i.e. codon usage, chromosome location, structural organization or regulation of the genes, do not show specific differences between the sets of the heterotopic isoproteins. There is no preference of gene location for any of the gene sets; only rarely are the genes for a mitochondrial and a cytosolic isoprotein located on the same chromosome. A variant of the 3' splice-site consensus exists in genes of nuclear-encoded mitochondrial proteins. This is most likely a consequence of the evolution of the genes in separate lineages before endosymbiosis led to the formation of mitochondria. Some of the original mRNA group II intron self-splicing functions of the endosymbiont seem to persist in part of the cytosolic splicing machinery and apparently require a specific consensus sequence [Juretic, N., Jaussi, R., Mattes, U. & Christen, P. (1987) Nucleic Acids Res.15, 10083-10086].

Animals↗
PubMed1994

Display of expression products of cDNA libraries on phage surfaces. A versatile screening system for selective isolation of genes by specific gene-product/ligand interaction.

Techniques for cloning cDNAs from bacteriophage libraries immobilised on solid supports are well established. However, these techniques do not allow selective enrichment of clones expressing proteins of interest. Screening of cDNA libraries would be simplified if the proteins encoded by cDNAs could be expressed on the surface of phage. Phage carrying genes encoding proteins for which a ligand is available can be selected directly by affinity interaction [Crameri, R. & Suter, M. (1993) Gene (Amst.) 137, 69-75]. The expression products from a cDNA library from Aspergillus fumigatus have been displayed on the surface of the filamentous phage M13 and screened for gene products binding to human serum IgE. The physical linkage of cDNA-encoded proteins to the genetic information required for their production, achieved by exploiting the high-affinity interaction of the Jun and Fos leucine zippers, allows screening of up to 1 x 10(10) independent clones in 50-microliters aliquots applied to a well of a microtiter plate coated with the ligand. Phage displaying IgE-binding proteins were selectively enriched 10(5)-10(6)-fold over non-specific phage after six rounds of growth and selection. The apparent molecular mass of the proteins selected from the cDNA library was in the range 20-40 kDa. Restriction enzyme analysis and preliminary sequence determination of 12 selected inserts revealed different sequences. The ability of the proteins to bind to human serum IgE was corroborated by enzyme-linked immunosorbent assay and by Western-blot analysis. The developed cloning strategy allows isolation of cDNAs encoding proteins for which a ligand is available and circumvents immobilisation of the libraries on solid-phase supports which hamper selective enrichment of clones expressing the desired protein.

Aspergillus fumigatus↗
PubMed1994

Shift in pH-rate profile and enhanced discrimination between dicarboxylic and aromatic substrates in mitochondrial aspartate aminotransferase Y70H.

Tyr70 of chicken mitochondrial aspartate aminotransferase was replaced with a histidine residue by oligonucleotide-directed mutagenesis. Aspartate aminotransferase Y70H retained at pH 7.5 13% of the activity toward dicarboxylic amino acids, whereas the activity toward aromatic amino acids was only 0.6% of that of the wild-type enzyme, corresponding to a 22-fold increase in the ratio of the activities toward these two types of substrates. In comparison to that of the wild-type enzyme, the low-pH limb of the pH-activity profile of the mutant enzyme was shifted to higher pH values, very likely reflecting the titration curve of the newly introduced histidine residue with a pKa' of 6.3. Apparently, a positively charged residue at position 70 abolishes enzymic activity. The spectrophotometrically determined pKa' value of the internal aldimine formed between pyridoxal 5'-phosphate and Lys258 in the mutant enzyme was 6.0, similar to that in the wild-type enzyme. The rate constant of the dissociation of pyridoxamine 5'-phosphate from the mutant enzyme was increased only 3 times over that of the wild-type enzyme, in contrast to the 80-fold increase in Escherichia coli aspartate aminotransferase Y70F [Toney, M. D., & Kirsch, J. F. (1987) J. Biol. Chem. 262, 12403-12405], suggesting that His70 can replace Tyr70 in forming a hydrogen bond to the coenzyme.

Amino Acid Sequence↗
PubMed1994

Effects of ionizing radiation and caffeine treatment on cyclin dependent kinase complexes in V79 hamster cells.

Exponentially growing V79 Chinese hamster lung fibroblasts irradiated with 7 Gy X-rays undergo cell cycle arrest in the S and G2 phases. These arrests are released, probably on completion of DNA repair. A premature release occurs after treatment of irradiated cells with caffeine. This release is accompanied by increased activity of the p34cdc2 serine/threonine protein kinase complex [Hain et al. (1993) Cancer Res. 53, 1507-1510]. We have investigated in V79 cells whether the association of p34cdc2 with its regulatory subunits cyclin A and B is affected by irradiation and subsequent caffeine treatment and found that this was not the case. The phosphorylation of p34cdc2 as assayed by mobility shift on SDS polyacrylamide gels was increased as early as 0.5 h after irradiation and decreased after subsequent caffeine treatment. A novel protein p40, detected with anti-PSTAIRE antibodies, appeared several fold more abundant than p34cdc2. Its phosphorylation state also changed after irradiation and after subsequent caffeine treatment.

Animals↗
PubMed1994

Genome lability in radiation-induced transformants of C3H 10T1/2 mouse fibroblasts.

We have been investigating radiation-induced neoplastic transformants of C3H 10T1/2 mouse fibroblasts for evidence of heritable changes. C3H 10T1/2 cells were treated with 8 Gy X rays. After approximately 8 weeks of culture, type II/III foci were isolated from the monolayer using cloning rings. Cell lines developed from these foci, and clones established from these cell lines, were examined for DNA content. The isolated focus-derived populations and derived clones often display aneuploidy and/or polyploidization. In one instance a clone (derived from a single cell) displayed multiple polyploidies. During passage the ploidy of many of the anomalous populations gradually reverted to the ploidy of the non-neoplastically transformed state. The morphological features associated with the neoplastic transformation event were nevertheless retained. The results demonstrate that exposure to radiation can induce, in association with morphological neoplastic transformation, a heritable, genomically labile state.

Animals↗
PubMed1993

Caffeine release of radiation induced S and G2 phase arrest in V79 hamster cells: increase of histone messenger RNA levels and p34cdc2 activation.

The serine/threonine protein kinase p34cdc2 activity in V79 hamster cells 4 h after treatment with 7-Gy X-rays is similar to that of unirradiated cells. Nevertheless, the irradiated cells are arrested in the S and G2 phases of the cell cycle. The mRNA concentrations of histones H1 and H4 are reduced by a factor of about 2 in irradiated cells compared to unirradiated cells, as opposed to the mRNAs of high-mobility group I(Y) and 17 proteins which appear unchanged. Both the p34cdc2 activity and the mRNA concentrations of the histones rise within 30 min after the release of the radiation induced cell cycle block by caffeine. During this time span the p34cdc2 activity increases about 4-fold and the histone mRNA levels recover approximately to those of an exponentially growing cell population. Regulatory pathways influenced in irradiated and in subsequently caffeine treated cells apparently interact with basic cell cycle control mechanisms.

Animals↗
PubMed1993

Mutant aspartate aminotransferase (K258H) without pyridoxal-5'-phosphate-binding lysine residue. Structural and catalytic properties.

If the pyridoxal-phosphate-binding lysine residue 258 of aspartate aminotransferase is exchanged for a histidine residue, the enzyme retains partial catalytic competence [Ziak, M., Jaussi, R., Gehring, H. and Christen, P. (1990) Eur. J. Biochem. 187, 329-333]. The three-dimensional structures of the mutant enzymes of both chicken mitochondria and Escherichia coli were determined at high resolution. The folding patterns of the polypeptide chains proved to be identical to those of the wild-type enzymes, small conformational differences being restricted to parts of the active site. If aspartate or glutamate was added to the pyridoxal form of the mutant enzyme [lambda max 392 nm and 330 nm (weak); negative CD at 420 nm, positive CD at 370 nm and 330 nm], the external aldimine (lambda max = 430 nm; negative CD at 360 nm and 430 nm) transiently accumulated. Upon addition of 2-oxoglutarate to the pyridoxamine form (lambda max 330 nm, positive CD), a putative ketamine intermediate could be detected; however, with oxalacetate, an equilibrium between external aldimine and the pyridoxal form, which was strongly in favour of the former, was established within seconds. The transamination cycle with glutamate and oxalacetate proceeds only three orders of magnitude more slowly than the overall reaction of the wild-type enzyme. The specific activity of the mutant enzyme is 0.1 U/mg at 25 degrees C and constant from pH 6.0 to 8.5. Reconstitution of the mutant apoenzyme with [4'-3H]pyridoxamine 5'-phosphate resulted in rapid release of 3H with a first-order rate constant kappa' = 5 x 10(-4) s-1 similar to that of the wild-type enzyme. Apparently, in aspartate aminotransferase, histidine can to some extent substitute for the active-site lysine residue. The imidazole ring of H258, however, seems too distant from C alpha and C4' to act efficiently as proton donor/acceptor in the aldimine-ketamine tautomerization, suggesting that the prototropic shift might be mediated by an intervening water molecule. Transmination of the internal to the external aldimine apparently can be replaced by de novo formation of the latter, and by its hydrolysis in the reverse direction.

Animals↗