Biomedical subjects

K Huebner

Publications and source records attributed to K Huebner.

At least 109 records · Page 6Linked to original sources

PubMed1995

Environmental factors may regulate BCL2 associated lymphomagenesis: a very low incidence of BCL2-MBR translocation in Poland.

A characteristic feature of follicular non-Hodgkin's lymphomas (FL) is a chromosome translocation t(14;18)(q32;q21). In American patients the t(14;18) can be found in the large majority (approximately 70%) of FL and in a significant (10-40%) percentage of diffuse large cell lymphomas (DLCL). However there are reports suggesting that geographic or racial factors may regulate genesis of lymphomas with BCL2 abnormalities. Herein we present results of molecular analysis for t(14;18) in lymphomas in Poland. Analyses were performed on 37 cases of FL, 55 cases of diffuse lymphomas (DL) and 39 cases of Hodgkin's disease (HD). By Southern and polymerase chain reaction BCL2 translocation within major breakpoint region was found only in 3 of 37 FL, 1 of 55 DL and 2 of 39 HD. These results are the lowest reported ratio. We hypothesize that environmental factors may regulate BCL2 associated lymphomagenesis.

Base Sequence↗

PubMed1994

Leucine-zipper dimerization motif encoded by the AF17 gene fused to ALL-1 (MLL) in acute leukemia.

Chromosome region 11q23 is involved in reciprocal chromosome translocations associated with human acute leukemias. These aberrations fuse the ALL-1 gene located at 11q23 to a series of partner genes positioned on a variety of human chromosomes. The fused genes encode chimeric proteins. Here we report the cloning and characterization of the ALL-1 partner at 17q21, the AF17 gene. The AF17 gene encodes a protein of 1093 amino acids, containing a leucine-zipper dimerization motif located 3' of the fusion point and a cysteine-rich domain at the N terminus. The latter can be arranged in three zinc fingers and shows homology to a domain within the protein Br140 (peregrin). AF17 contains stretches of amino acids previously associated with domains involved in transcriptional repression or activation. Based on features of AF17 and of the proteins encoded by the other partner genes analyzed and in conjunction with other recent studies, we propose a model in which ALL-1 rearrangements result in loss of function of the gene. In this model, the partner polypeptide plays an accessory role either by repressing activity of the truncated ALL-1 protein or by blocking the function of the normal protein presumably present in the leukemic cells.

Amino Acid Sequence↗

PubMed1994

Chromosome locations of genes encoding human signal transduction adapter proteins, Nck (NCK), Shc (SHC1), and Grb2 (GRB2).

Abnormalities due to chromosomal aberration or point mutation in gene products of growth factor receptors or in ras gene products, which lie on the same signaling pathway, can cause disease in animals and humans. Thus, it can be important to determine chromosomal map positions of genes encoding "adapter" proteins, which are involved in transducing signals from receptor tyrosine kinases to downstream signal recipients such as ras, because adaptor protein genes could also, logically, serve as targets of mutation, rearrangement, or other aberration in disease. Therefore, DNAs from panels of rodent-human hybrids carrying defined complements of human chromosomes were assayed for the presence of the cognate genes for NCK, SHC, and GRB2, three SH2 or SH2/SH3 (Src homology 2 and 3) domain-containing adapter proteins. Additionally, NCK and SHC genes were more narrowly localized by chromosomal in situ hybridization. The NCK locus is at chromosome region 3q21, a region involved in neoplasia-associated changes; the SHC cognate locus, SHC1, is at 1q21, and the GRB2 locus is at 17q22-qter telomeric to the HOXB and NGFR loci. Both SHC1 and GRB2 are in chromosome regions that may be duplicated in some tumor types.

Adaptor Proteins, Signal Transducing↗

PubMed1994

Common regions of deletion in chromosome regions 3p12 and 3p14.2 in primary clear cell renal carcinomas.

Nearly all clear cell renal cell carcinomas (RCCs) exhibit loss of alleles on the short arm of chromosome 3. Loss and mutation at the von Hippel-Lindau (VHL) gene at 3p25 probably occurs in most RCCs and, since the VHL gene was recently cloned, data on VHL involvement in RCCs is accumulating. However, the region 3p14-p12, a region that contains the familial RCC-associated t(3;8)(p14.2;q24) chromosome translocation and the small cell lung carcinoma-associated homozygous deletion at 3p13-12, has also been reported to exhibit allele loss in a large fraction of RCCs. In order to focus future studies on potential suppressor genes in the 3p14-p12 region, we have studied allele loss in 30 RCCs with 9 polymorphic simple sequence repeat markers spanning 3p21.1-p12. Partial losses in the 3p21-p12 region were observed, allowing determination of common regions of loss of heterozygosity overlap in 15 RCCs. Results suggested that most RCCs exhibit loss in a region which brackets the t(3;8) familial chromosome translocation at 3p14.2, and some show additional deletions within the U2020 small cell lung carcinoma deletion at 3p12.

Adenocarcinoma, Clear Cell↗

PubMed1994

Chromosome locations of human EMX and OTX genes.

We have determined the chromosomal localization of four human homeobox-containing genes, EMX1, EMX2, OTX1, and OTX2, related to Drosophila genes expressed in the developing head of the fly. Murine homologs of these genes are expressed in specific nested domains in the developing rostral brain of midgestation embryos. DNAs from a panel of 19 rodent-human hybrids, each carrying one or a few human chromosomes such that most human chromosome regions were represented, were tested for the presence of the four gene loci by filter hybridization to radiolabeled probes. Regional chromosomal localization was determined by similarly testing DNAs from hybrid mapping panels for each of the candidate chromosomes. Finally, fluorescence in situ hybridization of cosmid clones for these loci refined the locations, two of which were in the vicinity of previously mapped orphan homeobox genes and two of which were near each other. OTX2, the earliest and most widely expressed gene, maps to chromosome region 14q21-q22; the OTX1 locus maps to 2p13; EMX2 maps to 10q26.1; and EMX1, the most narrowly and lately expressed, maps to 2p14-p13. Thus, these homeobox-containing genes involved in brain development are not linked to any of the four HOX clusters on 7p15-p14, 17q21-q22, 12q12-q13, and 2q31. However, the OTX1 and EMX1 loci may be closely linked on or near 2p13, prompting speculation that a clustered gene structure could have functional significance, as is presumably the case for the HOX clusters.

Animals↗

PubMed1994

The human homologue of the retroviral oncogene qin maps to chromosome 14q13.

Chromosomal mapping of the human QIN gene (renamed FKH2 by the Human Genome Organization Nomenclature Committee) was initially accomplished by correlation of the presence of the QIN locus with specific chromosome regions in a rodent-human hybrid panel. This analysis revealed that the human QIN gene maps to chromosome region 14q11.2-->14q32, between the TCR and IGH loci. Further analysis by fluorescence in situ hybridization techniques with a human QIN genomic clone refined the human QIN gene localization to 14q13.

Chromosome Mapping↗

PubMed1994

Cloning and characterization of two members of the vertebrate Dlx gene family.

A number of vertebrate genes of the Dlx gene family have been cloned in mouse, frog, and zebrafish. These genes contain a homeobox related to that of Distalless, a gene expressed in the developing head and limbs of Drosophila embryos. We cloned and studied the expression of two members of this family, which we named Dlx5 and Dlx6, in human and mouse. The two human genes, DLX5 and DLX6, are closely linked in an inverted convergent configuration in a region of chromosome 7, at 7q22. Similarly, the two human genes DLX1 and DLX2 are closely linked in a convergent configuration at 2q32, near the HOXD (previously HOX4) locus. In situ hybridization experiments in mouse embryos revealed expression of Dlx5 and Dlx6 mRNA in restricted regions of ventral diencephalon and basal telencephalon, with a distribution very similar to that reported for Dlx1 and Dlx2 mRNA. A surprising feature of Dlx5 and Dlx6 is that they are also expressed in all skeletal structures of midgestation embryos after the first cartilage formation. The expression pattern of these genes, together with their chromosome localization, may provide useful cues for the study of congenital disorders in which there is a combination of craniofacial and limb defects.

Amino Acid Sequence↗

PubMed1994

Complementary DNA cloning of the alternatively expressed endothelial cell glycoprotein Ib beta (GPIb beta) and localization of the GPIb beta gene to chromosome 22.

Glycoprotein Ib beta (GPIb beta) exists in platelets disulfide-linked to glycoprotein Ib alpha (GPIb alpha), a major receptor for von Willebrand factor. Both GPIb alpha and GPIb beta are expressed in endothelial cells (EC). While the GPIb alpha mRNA and protein appear similar in platelets and EC, EC GPIb beta mRNA is larger than platelet GPIb beta and encodes a larger protein. We have cloned and sequenced EC GPIb beta cDNA and report a 2793-nucleotide sequence which contains a 411-amino acid open reading frame. The EC sequence contains all of the platelet cDNA sequence and all but three amino acids of the primary translation product. Like the genes encoding GPIb alpha, GPIX, and GPV, the GPIb beta gene appears simple in structure. Using human hamster hybrids, we have localized the GPIb beta gene to chromosome 22pter-->22q11.2. When we examined poly (A)+ RNA from several human tissues for GPIb beta mRNA expression, we found that GPIb beta mRNA was expressed in a variety of tissues but was most abundant in heart and brain, while GPIb alpha and GPIX mRNA expression was found only in lung and placenta at very low levels. The broad distribution of GPIb beta mRNA suggests that it may be playing a role different than or additional to its function in platelets.

Amino Acid Sequence↗

PubMed1994

Evolutionary conservation of the EPS8 gene and its mapping to human chromosome 12q23-q24.

We have previously isolated the coding sequence for a novel substrate for tyrosine kinases, eps8, from NIH3T3 fibroblasts. Eps8 was phosphorylated in vivo by several receptor tyrosine kinases (RTKs) and, upon overexpression, was able to enhance EGFR-mediated mitogenic signaling in NIH3T3 cells. To gain understanding of eps8 function as well as its role in normal and neoplastic proliferation, we cloned the human eps8 coding sequence and studied expression of the human RNA and protein, evolutionary conservation, and chromosomal location. In addition to a previously identified SH3 domain, the predicted amino acid sequence of human eps8 revealed a non-random distribution of prolines, clustered in a way to suggest SH3-binding sites and a putative PH domain. Eps8 was expressed in all epithelial and fibroblastic lines examined and in some, but not all, hematopoietic cells. An essential function of eps8 in cell growth regulation was underscored by its conservation during evolution, where eps8-related sequences were detected as early as in Saccharomyces cerevisiae. Finally, the human EPS8 locus was mapped to chromosome 12q23-q24.

3T3 Cells↗

PubMed1994

The human eps15 gene, encoding a tyrosine kinase substrate, is conserved in evolution and maps to 1p31-p32.

Employing an expression cloning approach for tyrosine kinase substrates, we have previously isolated the coding sequence for a novel putative EGFR substrate, eps15, from NIH3T3 fibroblasts. Eps15 displayed a receptor-specific pattern of tyrosine phosphorylation in vivo and was able to transform NIH3T3 cells upon overexpression. To gain understanding of eps15 function as well as its role in normal and neoplastic proliferation, we cloned the human eps15 coding sequence and studied expression of the human RNA and protein, evolutionary conservation, and chromosomal location. The close structural similarity of human eps15 with the murine homologue is indicated by 89% and 90% identity of nucleotide and predicted amino acid sequences, respectively. Using the human eps15 coding sequence as probe, we demonstrate that eps15 is member of a gene family that is highly conserved during evolution. An essential function of eps15 in cell growth regulation is underscored by our observation of ubiquitous expression at the transcript and the protein level in normal and malignant human cells. The human EPS15 locus maps to chromosome 1p31-p32, a region involved in deletion in neuroblastoma, translocations in acute lymphoblastic leukemia, and exhibiting a fragile site.

3T3 Cells↗

PubMed1993

The human TYRO3 gene and pseudogene are located in chromosome 15q14-q25.

Partial cDNAs of the human TYRO3 gene, encoding a putative receptor tyrosine kinase, and its processed pseudogene (TYRO3P) were cloned from human teratocarcinoma cell, bone marrow and melanocyte cDNA libraries. The tyrosine kinase homologous domains of TYRO3 and TYRO3P were sequenced and compared with each other and with the mouse TYRO3 gene. Abundant levels of the 4.2-kb TYRO3 mRNA were detected in human brain, and lower levels in other human tissues. TYRO3 and TYRO3P were both assigned to human chromosome 15q14-q25 by analysis of DNAs from somatic cell hybrids.

Amino Acid Sequence↗

PubMed1993

Cloning of the ALL-1 fusion partner, the AF-6 gene, involved in acute myeloid leukemias with the t(6;11) chromosome translocation.

Reciprocal chromosome translocations involving 11q23 are frequently associated with acute leukemias, with the t(4;11) translocation predominating among acute lymphoblastic leukemias, and the t(9;11), t(11;19) and t(6;11) translocations most common among acute myeloid leukemias. In each of these translocations the ALL-1 gene, located at 11q23 and constituting the human homologue of Drosophila trithorax, fuses to a specific gene on the partner chromosome to produce a chimeric protein. Here we report the cloning and the characterization of the partner gene from chromosome 6 (AF-6). AF-6 is expressed in a variety of cell types and encodes a protein of 1612 amino acids. The protein contains short stretches rich in prolines, charged amino acids, serines, or glutamines. In addition, the AF-6 protein contains the GLGF motif shared with several proteins of vertebrates and invertebrates thought to be involved in signal transduction at special cell-cell junctions.

Amino Acid Sequence↗

PubMed1993

A homozygous deletion within the carbonic anhydrase-like domain of the Ptprg gene in murine L-cells.

Protein tyrosine phosphatases, on purely theoretical grounds, were suggested as possible tumor suppressor genes, and receptor protein tyrosine phosphatase gamma (PTPRG) has been proposed, on the basis of its location at human chromosome region 3p14.2, specifically as a tumor suppressor gene for renal cell carcinoma. We have isolated murine genomic and complementary DNA clones for analysis and mapping of the murine Ptprg locus; interspecific backcross analysis showed that the Ptprg locus maps to the centromeric region of mouse chromosome 14. We also observed a homozygous, intragenic deletion in the Ptprg gene in all clonal derivatives of the original L-cell strain, a methylcholanthrene-treated mouse connective tissue cell line which produces sarcomas in syngeneic mice. The deletion begins in the second intron of the carbonic anhydrase-like domain of the Ptprg gene and ends in the fourth intron of the carbonic anhydrase-like domain. At the genomic level, perhaps several hundred kilobases of DNA are deleted; at the complementary DNA level the 400 base pairs comprising exons 2, 3, and 4 of the carbonic anhydrase-like domain are deleted. By reverse transcription polymerase chain reaction, an amplified fragment is produced from L-cell mRNA which is 400 base pairs shorter than the wild type gene product, suggesting that the deleted gene is transcribed and may produce a protein product. Thus, mouse L-cells have lost one Ptprg allele and sustained an intragenic deletion in the other; such allele loss and mutation frequently occur at tumor suppressor gene loci.

Amino Acid Sequence↗

PubMed1993

Characterization of human bone marrow-derived closed circular DNA clones.

Because of interest in mechanisms of recombination involved in chromosomal deletions in neoplastic disease, and their relation to possible rearrangements in normal tissues, we are studying circular DNA molecules from human tissue with a long-term goal of investigating them as possible by-products of physiologically relevant intrachromosomal recombination events. Covalently closed circular (ccc) DNA from human bone marrow was cloned in bacteriophage vectors, and fourteen clones chosen randomly from the cccDNA-derived library were characterized. Five clones originated from chromosome-specific centromeric alpha-satellite DNA; two clones carried highly repetitive sequences probably derived from interspersed repetitive elements; six clones were derived from single-copy chromosome-specific sequences which detected homologous rodent sequences; and one clone (EPM10) was derived from a small chromosome 11-specific sequence family which localized to chromosome regions 11cen and 11q14. Oligonucleotide primers derived from the cccDNA clones were used in polymerase chain reaction studies to show that (1) the EPM10 clone carried the circular junction, (2) several of the single-copy products could be detected in three different bone marrow cccDNA preparations, and (3) the Alu-PCR profile for bone marrow cccDNA showed distinct bands which were similar in four bone marrow cccDNA preparations.

Acute Disease↗

PubMed1993

FLT4 receptor tyrosine kinase gene mapping to chromosome band 5q35 in relation to the t(2;5), t(5;6), and t(3;5) translocations.

FLT4 is a recently cloned receptor tyrosine kinase cDNA, which is characterized by seven immunoglobulin-like loops in its extracellular domain. We have previously mapped the FLT4 gene to chromosome segment 5q33-qter using somatic cell hybrids. Here we have refined the localization to band 5q35 by fluorescence in situ hybridization and show that the gene is translocated to chromosomes 2 and 6 in the t(2;5)(p23;q35) and t(5;6)(q35;p21) translocations, respectively, of Ki-I-positive lymphomas, as well as to chromosome 3 in the t(3;5)(q25.1;q34) translocation, which is occasionally found in myelodysplastic syndromes and acute myeloid leukemia. No evidence was obtained for a rearrangement or deregulation of the translocated FLT4 gene. We further show that abundant FLT4 mRNA expression occurs only in erythroid and megakaryoblastoid cell lines among nine leukemia cell lines studied.

Chromosome Mapping↗

PubMed1993

Reassignment of the human ARH9 RAS-related gene to chromosome 1p13-p21.

The human ARH9 gene (originally rhoC), a member of the RAS gene superfamily, was initially isolated on the basis of cross-hybridization with a RAS-related cDNA from the marine snail Aplysia. The ARH9 gene locus was previously assigned to the telomeric region of chromosome 5q by isotopic chromosomal in situ hybridization and Southern analysis of somatic cell hybrid DNAs; the gene was noted to cosegregate with the CSF1 gene locus in human-rodent somatic cell hybrids carrying partial chromosomes 5, together with other human chromosomes. With the recent reassignment of the human CSF1 locus to chromosome 1, region p13-p21, it seemed important to reexamine the localization of the ARH9 gene, since it segregates 100% concordantly with the CSF1 locus in hybrid cells. Results of our investigation demonstrate that the ARH9 locus is also present in hybrids retaining chromosome 1, but not 5. Using hybrids carrying partial 1p, we mapped the ARH9 locus relative to other 1p loci, localizing the gene to the region 1p13-p31. Fluorescence in situ hybridization to metaphase chromosomes with a genomic ARH9 clone refined the gene's localization to chromosome 1, bands p13-p21.

Animals↗

PubMed1993

The leukemia inhibitory factor receptor (LIFR) gene is located within a cluster of cytokine receptor loci on mouse chromosome 15 and human chromosome 5p12-p13.

The leukemia inhibitory factor receptor (LIFR) gene was localized to human chromosome 5p12-p13 by somatic cell hybrid analysis. Interspecific backcross analysis revealed that the murine locus was on chromosome 15 in a region of homology with human chromosome 5p. In both human and mouse genomes, the LIFR locus was linked to the genes encoding the receptors for interleukin-7, prolactin, and growth hormone.

Animals↗

PubMed1993

Chromosomal localization of four human zinc finger cDNAs.

cDNA clones encoding zinc finger motifs were isolated by screening human placenta and T-cell (Peer) cDNA libraries with zinc finger (ZNF) consensus sequences. Unique cDNA clones were mapped in the human genome by rodent-human somatic cell hybrid analysis and in some cases in situ chromosomal hybridization. ZNF80 mapped to 3p12-3qter, ZNF7 was previously mapped to 8q24 and is here shown by in situ hybridization and use of appropriate hybrids to map telomeric to the MYC locus. ZNF79 mapped to 9q34 centromeric to the ABL gene and between a constitutional chromosomal translocation on the centromeric side and the CML specific ABL translocation on the telomeric side. ZNF77 mapped to 19p while ZNF78L1 (pT3) mapped to 19q. Chromosome 19 carries many ZNF loci and other genes with zinc finger encoding motifs; the pT3 clone additionally detected a locus designated ZNF78L2, which mapped to chromosome region 1p, most likely in the region 1p32 where the MYCL and JUN loci map.

Amino Acid Sequence↗