PubMed Health⌕ Search

Biomedical subjects

K Huebner

Publications and source records attributed to K Huebner.

At least 91 records · Page 5Linked to original sources
PubMed1996

Mapping of 22 Notl linking clones on human chromosome 3 by polymerase chain reaction and somatic cell hybrid panels.

Twenty-two human chromosome 3 derived and partially sequenced Notl linking clones were mapped using two somatic cell hybrid panels. Somatic cell hybrid mapping was performed by Southern hybridization and/or by polymerase chain reaction (PCR), using 300-500 bp CpG-rich sequences surrounding Notl sites. Thus, 22 new Notl site-tagged (sequence tagged sites) STSs were created, distributed over the entire human chromosome 3. The majority of these linking clones tag known or unknown expressed sequences (genes). Together with other physical and genetic mapping methods, localization of Notl linking clones facilitates the construction of a long-range physical map and, at the same time, a transcriptional map of human chromosome 3.

Animals↗
PubMed1996

The BAX gene maps to the glioma candidate region at 19q13.3, but is not altered in human gliomas.

The bax protein regulates apoptosis in a cellular pathway that involves both bcl-2 and p53, two molecules associated with human glioma tumorigenesis. We therefore evaluated the possibility that BAX functions as a glioma tumor suppressor gene. Somatic cell hybrid panels, fluorescence in situ hybridization and cosmid mapping localized the BAX gene to 19q13.3, approximately 300 kb centromeric to HRC. Thus BAX maps to the region of chromosome 19 most frequently deleted in gliomas. Routine and pulsed-field gel electrophoresis/Southern blotting studies, however, failed to reveal large-scale deletions or rearrangements of the BAX gene in gliomas. In addition, single strand conformation polymorphism analysis of all six BAX exons and flanking intronic sequences did not disclose mutations in 20 gliomas with allelic loss of the other copy of 19q. A C/T polymorphism was detected in intron 3 and was common in the general population. Therefore, although BAX maps to the glioma candidate region on the long arm of chromosome 19, BAX is probably not the 19q glioma tumor suppressor gene.

Base Sequence↗
PubMed1996

Trends in the postmortem epidemiology of invasive fungal infections at a university hospital.

BACKGROUND: Due to the lack of reliable diagnostic tools, clinical data on the significance of most invasive fungal infections are difficult to assess and information on frequency, disease pattern and prognostic impact still largely relies on autopsy data. METHODS AND RESULTS: To determine temporal trends in invasive fungal infections, we analyzed data from 8124 autopsies performed between 1978 and 1992 on patients who died at the University Hospital of Frankfurt/Main. During that period, a total of 278 invasive fungal infections were found. The prevalence rose from 2.2% (1978-82) and 3.2% (1983-87) to 5.1% in the most recent years (P < 0.001). Besides the emergence of mixed and unclassified infections, this was mainly due to a significant increase in Aspergillus infections (P < 0.001), whereas the prevalence of Candida infections was stable and even showed a declining trend within the last years. The highest infection rates were found in aplastic syndromes (68%), followed by AML (25%) and AIDS (19%). In the majority of cases (76%), invasive fungal infection was related to the immediate cause of death. However, the proportion of patients with endstage underlying conditions increased significantly over time from 53% to 80% (P < 0.001). Accordingly, the number of patients who were not considered terminally ill but had died from fungal infection dropped from 35% to 17% within the last years (P < 0.01). CONCLUSIONS: These observations document significant changes in frequency, aetiology and underlying disease processes in invasive fungal infections at autopsy and underscore the continuing need for more effective prevention, diagnosis, and treatment.

Adolescent↗
PubMed1996

Cloning, characterization, and chromosomal localization of a human 5-HT6 serotonin receptor.

We describe the cloning and characterization of a human 5-HT6 serotonin receptor. The open reading frame is interrupted by two introns in positions corresponding to the third cytoplasmic loop and the third extracellular loop. The human 5-HT6 cDNA encodes a 440-amino-acid polypeptide whose sequence diverges significantly from that published for the rat 5-HT6 receptor. Resequencing of the rat cDNA revealed a sequencing error producing a frame shift within the open reading frame. The human 5-HT6 amino acid sequence is 89% similar to the corrected rat sequence. The recombinant human 5-HT6 receptor is positively coupled to adenylyl cyclase and has pharmacological properties similar to the rat receptor with high affinity for several typical and atypical antipsychotics, including clozapine. The receptor is expressed in several human brain regions, most prominently in the caudate nucleus. The gene for the receptor maps to the human chromosome region 1p35-p36. This localization overlaps that established for the serotonin 5-HT1D alpha receptor, suggesting that these may be closely linked. Comparison of genomic and cDNA clones for the human 5-HT6 receptor also reveals an Rsal restriction fragment length polymorphism within the coding region.

Adenylyl Cyclases↗
PubMed1996

Detection of specific genetic alterations in cancer cells.

The genetic changes found in human neoplasms suggest that hematopoietic tumors develop mainly from inappropriate expression (usually overexpression) of a growth promoting gene (oncogene). In contrast, the progression to malignancy of carcinomas occurs mainly through loss of tumor suppressor genes. Gene therapy might be used to turn off an activated oncogene, eg, by antisense treatment, whereas gene therapy to overcome tumor suppressor gene loss necessarily would focus on gene replacement in the tumor cell or pharmacologically substituting for lost gene function. On the other hand, the protein products of mutations that activate oncogenes or that inactivate tumor suppressor genes are both potential tumor antigens. Increasingly, characterization of the molecular changes that contribute to the malignant phenotype provides information impacting on tumor diagnosis and patient prognosis.

Base Sequence↗
PubMed1995

Characterization of the complete genomic structure of the human WNT-5A gene, functional analysis of its promoter, chromosomal mapping, and expression in early human embryogenesis.

We report the complete genomic organization of the human WNT-5A gene, which encodes a cysteine-rich growth factor involved in cell-cell signaling during growth and differentiation. The gene comprises five exons with the terminal exon coding for a large 3'-untranslated region of approximately 6.5 kilobase pairs and utilizes multiple polyadenylation signals to generate at least four discrete transcripts. We discovered a new leader exon interrupted by a 411-base pair intron that was retained in our original cDNA cloning. The promoter region was located in a GpC-rich island and harbored numerous cis-acting elements including several GC boxes and Sp1, AP1, and AP2 binding motifs. It lacked TATA or CAAT boxes typical of housekeeping and growth factor genes. In support of this, primer extension revealed extension two transcription start sites. Transient cell transfection assays showed functional promoter activity for the 3.9-kilobase pair 5'-flanking region. Interestingly, internal and 5' deletions revealed tha the distal promoter was not required for full transcriptional activity and that the first 631 base pairs of WNT-5A harbored the strongest promoter activity. Using a panel of rodent-human hybrid DNAs carrying portions of chromosome 3p, we mapped the gene to 3p14.2-p21.1, between a constitutional and a familial renal cell carcinoma-associated translocation. In situ hybridization analyses of early human embryos at 28-42 days of gestation revealed that WNT-5A transcripts were not restricted to the developing brain and limbs but were also observed in the mesenchyme bordering the pharyngeal clefts and pouches and in the developing gonads and kidneys. The relatively high expression in the celomic epithelium and in the precursors of follicles and seminiferous tubules suggest a novel role for WNT-5A in germ-cell differentiation. This study provides the molecular basis for discerning the regulation of the WNT-5A gene and offers the opportunity to investigate genetic disorders linked to this important gene.

Animals↗
PubMed1995

Chromosome localization of human genes for clathrin adaptor polypeptides AP2 beta and AP50 and the clathrin-binding protein, VCP.

Clathrin-coated vesicles, involved in endocytosis and Golgi processing, have a surface lattice containing clathrin triskelia and stoichiometric amounts of additional components termed "assembly proteins," or APs. The AP form at the plasma membrane, AP2, is composed of two large subunits of 100-115 kDa, denoted AP2 alpha and AP2 beta, a medium chain of 50 kDa, designated AP50, and a small chain. We have determined human chromosomal locations of genes for a large AP2 beta (CLAPB1) and a medium (CLAPM1) AP subunit and of a novel clathrin-binding protein, VCP, that binds clathrin simultaneously with APs. Chromosomal in situ hybridization of a human genomic clone demonstrated that the CLAPM1 gene mapped to chromosome region 3q28. The gene for the CLAPB1 large subunit was mapped to 17q11.2-q12 by PCR amplification of an AP2 beta fragment from a panel of rodent-human hybrid DNAs. To map the human VCP sequence, a human-specific probe was made by RT-PCR of human mRNA using oligonucleotide primers from conserved regions of the porcine sequence. The amplified human fragment served as probe on Southern blots of hybrid DNAs to determine that the human VCP locus maps to chromosome region 9pter-q34.

Adaptor Protein Complex 2↗
PubMed1995

Characterization of the receptor protein tyrosine phosphatase gene product PTP gamma: binding and activation by triphosphorylated nucleosides.

A full-length cDNA for a novel isoform of the human receptor tyrosine phosphatase gamma gene (PTPRG) was overexpressed in Sf9 insect cells, and the gene product, PTP gamma, was purified and characterized. The protein was expressed as a M(r) approximately 185,000 protein accompanied by a M(r) approximately 120,000 putative cleavage product on SDS-PAGE analysis. The protein undergoes N-linked glycosylation and constitutive phosphorylation of serine residues. When assayed for tyrosine-specific phosphatase activity, PTP gamma dephosphorylated myelin basic protein at a pH optimum of 7.5 and a Km of 12.6 microM; reduced carboxyamidomethylated and maleylated lysozyme (RCM-lysozyme) at a pH optimum of 6.0 and a Km of 12 microM; and p-nitrophenylphosphate with a pH optimum of 5.5 and a Km of 3.5 mM. Phosphatase activity was inhibited by ZnCl2 and sodium orthovanadate; Mg2+, Mn2+, and Ca2+ ions were ineffective. The partially purified form of the enzyme was allosterically activated by triphosphorylated nucleosides, with a preference for purines. This activation was prevented by Mg2+ addition and did not occur when a purified form of the enzyme was utilized, suggesting that its activation depends on specific activating factors or conformational constraints. Interestingly, PTP gamma protein was specifically bound by an ATP-agarose matrix through its intracellular domain, suggesting a link between binding of nucleotides and activation of the phosphatase.

Adenosine Triphosphate↗
PubMed1995

Characterization of the mammalian YAP (Yes-associated protein) gene and its role in defining a novel protein module, the WW domain.

We report cDNA cloning and characterization of the human and mouse orthologs of the chicken YAP (Yes-associated protein) gene which encodes a novel protein that binds to the SH3 (Src homology 3) domain of the Yes proto-oncogene product. Sequence comparison between mouse, human, and chicken YAP proteins showed an inserted sequence in the mouse YAP that represented an imperfect repeat of an upstream sequence. Further analysis of this sequence revealed a putative protein module that is found in various structural, regulatory, and signaling molecules in yeast, nematode, and mammals including human dystrophin. Because one of the prominent features of this sequence motif is two tryptophans (W), we named it the WW domain (Bork, P., and Sudol, M. (1994) Trends Biochem. Sci. 19, 531-533). Since its delineation, more proteins have been shown to contain this domain, and we report here on the widespread distribution of the WW module and present a discussion of its possible function. We have also shown that the human YAP gene is well conserved among higher eukaryotes, but it may not be conserved in yeast. Its expression at the RNA level in adult human tissues is nearly ubiquitous, being relatively high in placenta, prostate, ovary, and testis, but is not detectable in peripheral blood leukocytes. Using fluorescence in situ hybridization on human metaphase chromosomes and by analyzing rodent-human hybrids by Southern blot hybridization and polymerase chain reaction amplification, we mapped the human YAP gene to chromosome band 11q13, a region to which the multiple endocrine neoplasia type 1 gene has been mapped.

Adaptor Proteins, Signal Transducing↗
PubMed1995

Involvement of the ALL-1 gene in a solid tumor.

Translocations involving chromosome band 11q23, found in 5-10% of human acute leukemias, disrupt the ALL-1 gene. This gene is fused by reciprocal translocation with a variety of other genes in acute lymphoblastic and myelogenous leukemias, and it undergoes self-fusion in acute myeloid leukemias with normal karyotype or trisomy 11. Here we report an alteration of the ALL-1 gene in a gastric carcinoma cell line (Mgc80-3). Characterization of this rearrangement revealed a three-way complex translocation, involving chromosomes 1 and 11, resulting in a partial duplication of the ALL-1 gene. Sequencing of reverse transcription-PCR products and Northern blot analysis showed that only the partially duplicated ALL-1 gene was transcribed, producing an mRNA with exon 8 fused to exon 2. This report of ALL-1 gene rearrangement in a solid tumor suggests that ALL-1 plays a role in the pathogenesis of some solid malignancies. The absence of the normal transcript in this cell line, in association with the loss-of-heterozygosity studies on chromosome 11q23 seen in solid tumors, suggests that ALL-1 is involved in tumorigenesis by a loss-of-function mechanism.

Animals↗
PubMed1995

Phospholipase C gamma-2 (Plcg2) and phospholipase C gamma-1 (Plcg1) map to distinct regions in the human and mouse genomes.

The phospholipase C gamma-2 (Plcg2) gene encodes an enzyme that plays a crucial role in intracellular signal transduction pathways. This enzyme is important because of its role in the generation of second messengers following the hydrolysis of phosphatidylinositol 4,5-bisphosphate. We have now determined the chromosomal location of this gene in the mouse and human genomes. An interspecific backcross involving AEJ/Gn and Mus spretus mice was used to localize the gene in mouse. A rodent/human somatic cell hybrid panel was used to map PLCG2 in the human genome. Our results position Plcg2 in the central region of mouse chromosome 8. We also show that PLCG2 maps to the long arm of human chromosome 16, in the region q22-qter. Plcg2 does not map near its most closely related family member, Plcg1, in either genome, indicating that the mammalian Plcg genes belong to a dispersed family.

Animals↗
PubMed1995

Meis1, a PBX1-related homeobox gene involved in myeloid leukemia in BXH-2 mice.

Leukemia results from the accumulation of multiple genetic alterations that disrupt the control mechanisms of normal growth and differentiation. The use of inbred mouse strains that develop leukemia has greatly facilitated the identification of genes that contribute to the neoplastic transformation of hematopoietic cells. BXH-2 mice develop myeloid leukemia as a result of the expression of an ecotropic murine leukemia virus that acts as an insertional mutagen to alter the expression of cellular proto-oncogenes. We report the isolation of a new locus, Meis1, that serves as a site of viral integration in 15% of the tumors arising in BXH-2 mice. Meis1 was mapped to a distinct location on proximal mouse chromosome 11, suggesting that it represents a novel locus. Analysis of somatic cell hybrids segregating human chromosomes allowed localization of MEIS1 to human chromosome 2p23-p12, in a region known to contain translocations found in human leukemias. Northern (RNA) blot analysis demonstrated that a Meis1 probe detected a 3.8-kb mRNA present in all BXH-2 tumors, whereas tumors containing integrations at the Meis1 locus expressed an additional truncated transcript. A Meis1 cDNA clone that encoded a novel member of the homeobox gene family was identified. The homeodomain of Meis1 is most closely related to those of the PBX/exd family of homeobox protein-encoding genes, suggesting that Meis1 functions in a similar fashion by cooperative binding to a distinct subset of HOX proteins. Collectively, these results indicate that altered expression of the homeobox gene Meis1 may be one of the events that lead to tumor formation in BXH-2 mice.

Amino Acid Sequence↗
PubMed1995

Chromosomal mapping of the genes GPRK5 and GPRK6 encoding G protein-coupled receptor kinases GRK5 and GRK6.

G protein-coupled receptor kinases (GRKs) play an important role in phosphorylating and regulating the activity of a variety of G protein-coupled receptors. Chromosomal mapping of the human genes for the two most recently identified members of the GRK family, GRK5 (GPRK5) and GRK6 (GPRK6), was accomplished by correlation of the presence of the GPRK5 and GPRK6 loci with specific chromosome regions in a rodent-human hybrid panel. These analyses revealed that GPRK5 maps to chromosome region 10q24-->qter while GPRK6 maps to 5q35. A GPRK6 related locus maps to 13pter-->q21.

Animals↗
PubMed1995

Abnormalities of chromosome 5q correlate with morphologic features of better prognosis in clear cell renal carcinomas.

Aberrations of the long arm of chromosome 5 (5q) were studied in 79 clear cell renal carcinomas (clear cell RCC) by LOH (loss of heterozygosity) method, using microsatellite markers D5S107, CRTL1, LNS-CA, IL-9.RP1, CFS1R and GeneScan analysis software. Alterations of chromosome 5q were detected in 42% of cases. We found, that accumulation of genomic abnormalities at multiple loci of 5q, especially in 5q21-qter region, where genes for cytokines are located, correlates with morphologic features of better prognosis.

Adenocarcinoma, Clear Cell↗
PubMed1995

Non-isotopic procedure with silver staining of polyacrylamide gels in detection of genomic abnormalities in tumors using microsatellites.

Microsatellite-based PCR (polymerase chain reaction) with silver staining of polyacrylamide gels as an alternative approach to detect genomic abnormalities in tumors has been developed. In experiments with a series of primers for microsatellite sequences located on human chromosome 5 we found that a 2- to 4-fold increase or decrease in the ratio of amount of allelic microsatellite sequences can be reliably assessed from the relative intensity of corresponding PCR products. Results of the studies of renal carcinoma cell lines carrying increased or decreased numbers of specific allelic markers on chromosome 5 assessed by cytogenetics, Southern blotting-restriction fragment length polymorphism and microsatellite analyses were consistent. Microsatellite studies performed on samples obtained from formalin-fixed paraffin-embedded archival material allowed detection of genomic abnormalities of chromosome 5 in five of ten primary renal cell carcinomas.

Base Sequence↗