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H Küster

Publications and source records attributed to H Küster.

25 records · Page 2Linked to original sources
PubMed1992

The gene and cDNA for the human high affinity immunoglobulin E receptor beta chain and expression of the complete human receptor.

The high affinity IgE receptor (Fc epsilon RI) is a tetrameric hetero-oligomer composed of an alpha chain, a beta chain, and two disulfide-linked gamma chains. The beta chain contains four transmembrane (TM) segments and long cytoplasmic domains that are thought to play an important role in intracellular signaling. We now report the structural characterization and the sequence of the complete human beta gene and cDNA. The gene spans approximately 10 kilobases and contains seven exons. There is a single transcription initiation site preceded by a TATA box. The first exon codes for the 5'-untranslated region and a portion of the N-terminal cytoplasmic tail. TM-1 is encoded in exons 2 and 3, TM-2 in exons 3 and 4, TM-3 in exon 5, and TM-4 in exon 6. The seventh and final exon encodes the end of the C-terminal cytoplasmic tail and the 3'-untranslated sequence. The human beta gene appears to be a single copy gene. Two corresponding transcripts, detected as a doublet around 3.9 kilobases, are present in cells of mast cell and basophil lineage from different individuals, but not in the other hematopoietic cells tested here. The human beta protein is homologous to rodent beta. The consensus amino acid sequences of human, mouse, and rat beta show 69% identical residues. Analysis of the surface expression of transfected receptors indicates that human alpha gamma and alpha beta gamma complexes are expressed with comparable efficiency. Human beta interacts with human alpha more efficiently than does rat beta, and both rat and mouse beta interact with their corresponding alpha more efficiently than does human beta, demonstrating a species specificity of the alpha/beta interaction.

Amino Acid Sequence↗
PubMed1991

The high-affinity receptor for immunoglobulin E: a target for therapy of allergic diseases.

The high-affinity receptor for IgE (Fc epsilon RI) on mast cells and basophils is a tetrameric complex, alpha beta gamma 2. Here we summarize the latest developments on the structure and function of this receptor. By genetic transfer, we have engineered a cell line secreting substantial amounts of a peptide containing exclusively the extracellular domain of the alpha-subunit. This domain by itself is sufficient to mediate high-affinity binding of IgE. Glycosylation and the presence of the other subunits are not necessary for the binding function. The gamma-subunit of Fc epsilon RI is part of other receptors such as Fc gamma RIII and the T cell receptor, and therefore is likely to play an important although still undefined functional role. A detailed knowledge of how the receptor interacts with IgE and induces cellular degranulation may lead to the design of new therapeutic approaches to allergic diseases. The potential strategies are discussed.

Animals↗
PubMed1990

Characterization and expression of the gene for the human Fc receptor gamma subunit. Definition of a new gene family.

The high affinity IgE receptor, Fc epsilon RI, is one of the key molecules involved in allergic reactions. It is a tetrameric complex (alpha beta gamma 2). The gamma chains from Fc epsilon RI are also subunits of other Fc receptors. We have isolated, characterized, and sequenced the gene for the human gamma chain of Fc epsilon RI. It consists of five exons and spans 4 kilobases. The leader sequence is encoded by two exons, the second of which also contains the short extracellular domain, the hydrophobic transmembrane region, and the beginning of the cytoplasmic tail. Three short exons encode the remaining of the polypeptide and the 3'-untranslated flanking sequence. The transcription initiation sites have been mapped. Comparison between the gene structures of the gamma chain of the Fc receptor and of the zeta chain of the T-cell receptor indicates that these genes have evolved from a common ancestor by duplication and that they define a new gene family. In addition to being localized on the same chromosome, both genes show an analogous organization of their exons. A high level of homology is found in three of their respective exons, and the splice sites between them are identical. Furthermore, gamma and zeta chains are essential for surface expression of their respective receptors. Therefore, gamma chains of Fc receptors and zeta chains of T-cell receptors may also define a new family of functionally related polypeptides. Expression studies in COS cells show that the human gamma chain alone is sufficient to achieve expression of the human alpha chain on the cell surface, whereas both beta and gamma chains are required for the surface expression of the rodent alpha chain.

Amino Acid Sequence↗
PubMedDate not supplied

CSF interleukin-6 in neonatal Citrobacter ventriculitis after meningitis.

An infant with neonatal severe Citrobacter koseri (formerly Citrobacter diversus) meningoencephalitis developed necrosis with multicystic regression of both hemispheres. The ventriculitis persisted over months in spite of antibiotic therapy. The treatment succeeded with cefotaxime in a high dose (300 mg/kg/day) without surgical intervention. The infant had been previously treated with cefotaxime (200 mg/kg/day) over 5 weeks. High levels of CSF interleukin-6 (IL-6) permitted to attribute persisting CSF pleocytosis in spite of sterile CSF cultures to chronic infection and not to reminiscence of brain necrosis. This report reveals two main points. On the one hand, the importance of therapy monitoring with IL-6 in CSF for the consequent treatment of Citrobacter meningitis and on the other hand, high-dose cefotaxime (300 mg/kg/day) treatment of Citrobacter ventriculitis, which succeeded without surgical intervention.

Biomarkers↗
PubMedDate not supplied

The sucrose synthase gene is predominantly expressed in the root nodule tissue of Vicia faba.

To analyze nodule-specific gene expression in broadbean, we have isolated and sequenced sucrose synthase (SUCS) cDNAs from a broadbean nodule-specific cDNA library. The most 5' sequences identified from these partial cDNAs were used as a molecular probe to isolate a full-length sucrose synthase transcript sequence from a cDNA library derived from broadbean nodule mRNA. This cDNA (VfSUCS) contained a reading frame of 2,418 bp, coding for a protein of 806 amino acids with a deduced molecular weight of 92.5 kDa. The DNA as well as the deduced amino acid sequence displayed substantial homologies (68-95%) to other plant SUCS sequences. Northern and RNA dot blot experiments demonstrated that this gene is strongly expressed in the broadbean nodule tissue. An at least 10-fold lower VfSUCS expression could be detected in the uninfected root, hypocotyl, stem, and flower tissues of broadbean, whereas only traces of VfSUCS transcripts were recognizable in the broadbean leaf tissues. VfSUCS transcripts could not be detected in mature seeds of broadbean. Because of this significantly nodule-amplified type of expression, we refer to VfSUCS as a nodulin gene and propose to designate it VfNOD93 (Nuf-93) for the sucrose synthase enzyme).

Amino Acid Sequence↗
PubMedDate not supplied

Analysis of the Rhizobium meliloti genes exoU, exoV, exoW, exoT, and exoI involved in exopolysaccharide biosynthesis and nodule invasion: exoU and exoW probably encode glucosyltransferases.

Sequence analysis of a 5.780-kb DNA fragment originating from megaplasmid 2 of Rhizobium meliloti 2011 involved in biosynthesis of exopolysaccharide I (EPS I) and invasion of alfalfa nodules revealed the presence of five exo genes designated exoU, exoV, exoW, exoT, and exoI. ExoT resembled transmembrane proteins, whereas ExoI displayed a characteristic signal peptide. Sequence comparisons with several polysaccharide-polymerizing enzymes of both prokaryotic and eukaryotic origin indicated that exoW and exoU encode glucosyltransferases. Moreover, ExoV displayed weak homologies to the ExoO, ExoA, ExoL, and ExoM proteins of R. meliloti, which are also discussed as glucosyltransferases. Using exo-lacZ transcription fusions in connection with plasmid integration mutagenesis, promoters were identified in front of exoI, exoT, exoW, exoV, and exoU.R. meliloti 2011 strains with mutations in exoT, exoW, exoV, and exoU produced no detectable EPS I and were unable to infect alfalfa nodules, whereas exoI mutants synthesized a reduced amount of EPS I and did infect alfalfa nodules.

Amino Acid Sequence↗