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G Senger

Publications and source records attributed to G Senger.

At least 37 records · Page 2Linked to original sources
PubMed1995

Cloning of ATAC, an activation-induced, chemokine-related molecule exclusively expressed in CD8+ T lymphocytes.

A cDNA clone, designated ATAC, was isolated from a collection of human T cell activation genes. Analysis of tissue distribution determined that ATAC mRNA of approximately 0.9 kb is exclusively expressed in activated CD8+ T cells. Induction of the ATAC gene requires stimulation by both phorbol 12-myristate 13-acetate and Ca2+ ionophore A23187 ("two-signal gene") and is fully abrogated by the immunosuppressive agent cyclosporin A. Upon stimulation, ATAC mRNA is detectable within 30 min, maximal expression is seen after 4 h. The polypeptide encoded by the open reading frame of ATAC mRNA is 114 amino acids long with a calculated M(r) of 12.52 kDa. The structural features predict the cleavage and secretion of a mature ATAC protein of approximately 10 kDa from the 12.52-kDa precursor. ATAC is highly similar to a very recently identified murine molecule designated lymphotactin both at the cDNA (73.8% identity) and the protein (61.4% identity) levels, and related to members of the C-C and C-X-C chemokine families. Two variants of the ATAC protein were expressed and tested for chemotaxis and Ca2+ release on a variety of target cells. The ATAC gene was located to chromosome 1q23.

Amino Acid Sequence↗
PubMed1995

An integrated map of human chromosome 6p23.

The human chromosomal band 6p23 is a Giemsa-negative (light) band that may be expected to be relatively gene rich. The genes for spinocerebellar ataxia type 1 (SCA1), guanosine monophosphate reductase (GMPR), DEK involved in a subtype of acute myeloid leukemia (AML), and the folate-sensitive fragile site FRA6A, have already been mapped to 6p23. Recent linkage data have suggested evidence for a susceptibility locus for schizophrenia in the region. We have constructed a single YAC contig of approximately 100 clones spanning the entire 6p23 band from 6p22.3 to 6p24.1 and covering 7.5-8.5 Mb of DNA. The YAC contig contains 55 markers including genetically mapped STSs, physically mapped STSs, anonymous STSs, anonymous ESTs, and ESTs from the genes mapped to the region. The order of the genetically mapped STSs is consistent with their order in the contig and some of the markers not resolved on the genetic map have been resolved by the YACs. Four of the YACs from 6p23 and covering approximately 3 Mb of DNA have been used to isolate approximately 300 cosmids from a flow-sorted human chromosome 6 cosmid library, which have been organized into pockets. The proposed susceptibility locus for schizophrenia is most closely linked to D6S260, which is located within the YAC contig along with genetic markers < or = 5 cM on either side. Therefore, the presented materials are valuable reagents for characterization of the genomic region implicated in schizophrenia.

Base Sequence↗
PubMed1994

Molecular cloning of the B-CAM cell surface glycoprotein of epithelial cancers: a novel member of the immunoglobulin superfamily.

The human F8/G253 antigen, B-CAM, is a cell surface glycoprotein that is expressed with restricted distribution pattern in normal fetal and adult tissues, and is up-regulated following malignant transformation in some cell types. We have isolated a complementary DNA for B-CAM using an expression cloning technique. The complementary DNA (EMBL accession number X80026) encodes a 588-amino acid protein which is a novel member of the immunoglobulin superfamily with a characteristic V-V-C2-C2-C2 immunoglobulin domain structure. This structure has been described previously for the human MUC18 melanoma antigen (31% amino acid identity) and chicken and rat versions of a neural adhesion molecule referred to as SC1/DM-GRASP/BEN or KG-CAM, respectively (26% amino acid identity). This homology is suggestive of a role for B-CAM in cell-cell or cell-matrix adhesion. The gene for B-CAM has been mapped by fluorescence in situ hybridization to chromosome 19q13.2-13.3.

Activated-Leukocyte Cell Adhesion Molecule↗
PubMed1994

Proteasome components with reciprocal expression to that of the MHC-encoded LMP proteins.

BACKGROUND: Intracellular proteins are processed into small peptides that bind HLA class I molecules of the major histocompatibility complex (MHC) in order to be presented to T lymphocytes. The proteasome, a multi-subunit protease, has recently been implicated in the generation of these peptides. Two genes encoding proteasome subunits, LMP2 and LMP7, are tightly linked to the TAP peptide transport loci in the class II region of the human MHC. Inclusion of the LMP subunits may alter proteasome activity, biasing it towards the production of peptides with carboxyl termini appropriate for binding HLA class I molecules. Nevertheless, mutant cells that lack the LMP genes are able to process and present antigens at the cell surface at similar levels to wild-type cells. These results raise questions about the role of the proteasome, and in particular of the LMP subunits, in antigen processing. RESULTS: We have cloned the genes encoding a new proteasome subunit, MB1, which is closely related to LMP7, and that encoding a second subunit, Delta, which is closely related to LMP2. Expression of the MB1 and delta genes is reciprocal to that of the LMP genes: MB1 and delta are up-regulated in mutant cell lines lacking LMPs and down-regulated in the presence of gamma-interferon. The MB1 and delta genes are found to be located on chromosomes 14 and 17, respectively, raising interesting evolutionary questions about how the LMP genes independently became incorporated into the MHC. CONCLUSIONS: We suggest that the subtle phenotype of LMP-deficient cell lines results from the compensatory expression in these lines of two other proteasome subunits, MB1 and Delta.

Amino Acid Sequence↗
PubMed1994

Characterization of a microdissection library from human chromosome region 3p14.

Structural alterations in human chromosome region 3p14-p23 resulting in the inactivation of one or more tumor suppressor genes are thought to play a pathogenic role in small cell lung cancer, renal cell carcinoma, and other human neoplasms. To identify putative tumor suppressor genes, 428 recombinant clones from a microdissection library specific for human chromosome region 3p14 were isolated and characterized. Ninety-six of these (22.5%) were human single-copy DNA sequences, 57 of which were unique sequence clones. Forty-four of these were mapped to the microdissected region using a cell hybrid mapping panel. Within this mapping panel, four probes detected two new chromosome breakpoints that were previously indistinguishable from the translocation breakpoint t(3;8) in 3p14.2 in hereditary renal cell carcinoma. One probe maps to the homozygously deleted region of the small cell lung cancer cell line U2020. In addition, microdissection clones have been shown to be suitable for isolation of yeast artificial chromosomes.

Animals↗
PubMed1994

Cloning and characterization of human phosphatase inhibitor-2 (IPP-2) sequences.

cDNA clones similar to rabbit muscle phosphatase inhibitor-2 (IPP-2) were isolated from human libraries. On Northern blots two transcripts of approximately 2kbp and approximately 4kbp were detected in all tissues tested. Analysis of cDNA sequences showed that the longer transcripts were similar to the shorter clones but contained extended 3' ends. The human nucleotide sequence was highly homologous (94% identity) to the rabbit IPP-2 sequence and encoded a peptide of 205 amino acids. IPP-2 sequences were highly conserved throughout vertebrates. Southern hybridization results were consistent with the existence of a family of related IPP-2 sequences in the human genome. Most of these are likely to be pseudogenes, since all of the cDNA clones examined could have originated from a single gene. By in situ hybridization IPP-2 sequences were mapped to several different human chromosomes. We sequenced one gene located in the major histocompatibility complex (MHC) on Chromosome (Chr) 6 that contained the entire coding region of IPP-2.

Amino Acid Sequence↗
PubMed1994

The origin of human chromosome 2 analyzed by comparative chromosome mapping with a DNA microlibrary.

Fluorescence in situ hybridization (FISH) of microlibraries established from distinct chromosome subregions can test the evolutionary conservation of chromosome bands as well as chromosomal rearrangements that occurred during primate evolution and will help to clarify phylogenetic relationships. We used a DNA library established by microdissection and microcloning from the entire long arm of human chromosome 2 for fluorescence in situ hybridization and comparative mapping of the chromosomes of human, great apes (Pan troglodytes, Pan paniscus, Gorilla gorilla, Pongo pygmaeus) and Old World monkeys (Macaca fuscata and Cercopithecus aethiops). Inversions were found in the pericentric region of the primate chromosome 2p homologs in great apes, and the hybridization pattern demonstrates the known phylogenetically derived telomere fusion in the line that leads to human chromosome 2. The hybridization of the 2q microlibrary to chromosomes of Old World monkeys gave a different pattern from that in the gorilla and the orang-utan, but a pattern similar to that of chimpanzees. This suggests convergence of chromosomal rearrangements in different phylogenetic lines.

Animals↗
PubMed1994

Cloning of the region between HLA-DMB and LMP2 in the human major histocompatibility complex.

The human MHC is one of the most extensively mapped regions of the human genome. Almost all of the class II region of the MHC has already been cloned in cosmids but a gap remained between the DMB and LMP2 genes. Previously, screening of several complete cosmid libraries had failed to bridge this gap, which may contain novel antigen processing or presentation genes. We constructed cosmid libraries from two different sources in order to clone the region: (a) a library with fourfold coverage made from flow-sorted human chromosome 6 DNA and (b) a library derived from a yeast artificial chromosome clone spanning the region. Using this saturation approach, cosmid clones were eventually isolated over the region of interest. A single bacteriophage P1 clone was also obtained spanning the region. The YAC, cosmid, and P1 physical maps were consistent and the distance between the DMB and LMP2 genes was measured as 70 kb. It is not clear why DMB to LMP2 is infrequently represented in cosmid libraries, but the clones that we have obtained will now enable us to search for new coding sequences.

Bacteriophage P1↗
PubMed1994

A novel gene encoding a B-box protein within the BRCA1 region at 17q21.1.

A novel cDNA clone was isolated using a polyclonal serum directed against partially purified ovarian carcinoma antigen CA125. The deduced peptide sequence lacked membrane protein characteristics expected for CA125 but encompassed a B-box/coiled coil motif present in many genes with transformation potential. The gene was mapped by fluorescence in situ hybridization within the minimum region known to contain the familial breast/ovarian carcinoma gene, BRCA1. YAC and cosmid clones were isolated and used to refine the location of this gene adjacent and proximal to the RNU2 locus. The exon structure of the gene was determined. Extensive SSCP and sequence analysis of over 100 tumour and normal DNAs from familial and sporadic breast cancers and sporadic ovarian cancers failed to detect mutations in the coding region of this gene.

Amino Acid Sequence↗
PubMed1994

Released chromatin: linearized DNA for high resolution fluorescence in situ hybridization.

Free DNA was prepared from routinely harvested and fixed cells for high resolution FISH mapping using either a sodium hydroxide/ethanol mixture or 70% formamide. Hybridization signals from cosmid probes appeared as extended lines. The average length of signals on DNA prepared with sodium hydroxide was significantly greater than with formamide. A set of overlapping cosmids from the HLA class II region was used to determine how precisely the actual overlap or gap between probes can be calculated from the measured overlap or gap between their signals. Lengths of the probe signals and their known kilobase lengths were used as an internal ruler. The mean values calculated from the measured length from 30 or more signals for each probe pair showed remarkable conformity with the known kilobase lengths of their overlaps and gaps. Immediately adjacent probes could also be ordered on the released DNA. These simple procedures dramatically increase the speed with which relationships between probes can be determined during contig construction.

Chromatin↗
PubMed1994

Defective expression of CD40 ligand on T cells causes "X-linked immunodeficiency with hyper-IgM (HIGM1)".

X-linked immunodeficiency with hyper-IgM (HIGM1) is a rare disorder, characterized by recurrent infections associated with very low or absent IgG and IgA, and normal to increased IgM serum levels. The disease has been earlier mapped to the q26-27 region of the X-chromosome. We have identified a novel molecule expressed on the surface of activated T cells, which was designated TRAP (Tumor necrosis factor Related Activation Protein), and could demonstrate that TRAP is a ligand for the CD40 receptor expressed on B cells. Our mapping of the TRAP gene to the Xq26.3-27.1 region suggested a causal relationship to HIGM1. Further work revealed that various mutations of the TRAP/CD40 ligand (CD40L) gene may lead to a defective expression of the TRAP/CD40L molecule on the T-cell surface in HIGM1 patients. A combination of structural and functional analyses finally demonstrated that the failure of TRAP/CD40L on T cells to interact with CD40 on B cells is responsible for the inefficient T-cell help for B cells observed in HIGM1. The observations made in HIGM1 allowed us to conclude that TRAP/CD40L is not required for IgM synthesis. In contrast, functional expression of TRAP is a prerequisite for effective immunoglobulin isotype switching and subsequent production of IgG, IgA and IgE by B cells in vivo. The interaction of TRAP/CD40L with CD40 thus provides a very critical link between the cellular and the humoral part of the immune system. The knowledge of TRAP/CD40L cDNA sequence, the availability of various reagents for the testing of expression and function of TRAP/CD40L, and our recent elucidation of the exon-intron structure of the TRAP/CD40L gene now provide all necessary tools for early diagnosis of affected patients and the detection of female carriers of HIGM1. The available information will also provide a basis for future attempts at gene therapy in this disease.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1994

NOT, a human immediate-early response gene closely related to the steroid/thyroid hormone receptor NAK1/TR3.

By analyzing the early genetic response of human T cells following mitogenic activation we have identified NOT, a member of the steroid/thyroid hormone family of receptors. NOT has all structural features of steroid/thyroid hormone receptors (C2C2 zinc-finger domain, ligand binding domain), but is rapidly and only very transiently expressed after cell activation, which is clearly at variance with classical steroid receptors such as glucocorticoid or estrogen receptors. NOT gene induction is independent of de novo protein synthesis, defining NOT as an immediate-early response gene. Short-lived NOT mRNA (4.2 kilobases) expression could be observed in vitro in a greater number of tissue types following activation by a variety of distinct stimuli. In vivo, NOT mRNA expression was detected exclusively in the brain, where a very strong signal was observed. By immunoblot analysis of human T cell lysates with NOT specific antisera two activation-dependent protein bands (66 and 59 kilodaltons) could be detected. NOT gene was localized to human chromosome 2q22-q23. Sequence comparison revealed that NOT is the human homolog of the murine NURR1 and rat RNR-1. Moreover NOT is closely related to NAK1/TR3, a previously identified human orphan steroid receptor. Several lines of evidence indicate that NOT and NAK1/TR3 form a distinct and exclusive subgroup of orphan steroid receptors, whose expression characteristics in vitro and in vivo resemble the expression of nonsteroid immediate-early transcription factors such as jun and fos. NOT and NAK1/TR3 thus may function as general coactivators of gene transcription rather than participate in the induction of specific target genes, as is the case with classical steroid receptors.

Amino Acid Sequence↗
PubMed1993

New vector for transfer of yeast artificial chromosomes to mammalian cells.

A modification vector has been constructed to facilitate the transfer of yeast artificial chromosomes (YACs) to mammalian cells in culture by targeting a dominant selectable marker (G418 resistance) to the right arm of pYAC4 clones. The ADE2 gene is used for yeast selection with consequent disruption of the URA3 gene, allowing direct modification of YACs within the common host strain AB1380, and providing a simple test for correct targeting. This vector has been tested by modification of a 550-kb YAC containing part of the human MHC class II region and transfer to CHO cells by protoplast fusion. Analysis of 15 independent G418-resistant CHO lines obtained following fusion suggests the majority contain a complete YAC with moderate amplification in some lines.

Animals↗
PubMed1993

Fine mapping of the human MHC class II region within chromosome band 6p21 and evaluation of probe ordering using interphase fluorescence in situ hybridization.

Eight previously well-characterized and mapped probes derived from the human major histocompatibility complex (MHC) class II region were used to investigate the advantages and limitations of fluorescence in situ hybridization (FISH) techniques for fine mapping. The class II region of the MHC was localized within subband 6p21.31 by in situ hybridization on metaphase chromosomes that were banded by immunofluorescence staining with an antibody against 5-bromodeoxyuridine (BrdU). Ordering of probes that were separated by up to 900 kb was achieved by simultaneous hybridization of two or three probes on interphase nuclei. Three-color FISH proved to be an excellent method for ordering of probes within distances of 200-1,000 kb. Under certain conditions, closer probes could be ordered by comparing measured distances between their hybridization signals in interphase nuclei. A linear correlation between measured interphase distances and kilobase distances was observed up to 500 kb. With increasing distances, the measurements become more inaccurate due to chromatin folding.

Chromosome Mapping↗
PubMed1992

Cloning of TRAP, a ligand for CD40 on human T cells.

A cDNA clone, designated TRAP (TNF-related activation protein) was isolated from a collection of T cell activation genes. The polypeptide encoded by a mRNA of approx. 2.3 kb is 261 amino acids long with a calculated M(r) of 29.3 kDa. The structural features predict a type II transmembrane protein, but are also compatible with a secreted form. TRAP is highly similar to an identified murine CD40 ligand both at the cDNA (82.8% identity) and the protein (77.4% identity) levels, and related to tumor necrosis factor/lymphotoxin. Expressed in a murine myeloma, TRAP was identified as a ligand for CD40 by binding to a soluble CD40 construct. TRAP mRNA is expressed in a T cell-specific fashion with a maximum at 8 h after stimulation. The TRAP gene is located in the q26.3-q27.1 region of the X chromosome.

Amino Acid Sequence↗