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Biomedical subjects

U Francke

Publications and source records attributed to U Francke.

At least 109 records · Page 6Linked to original sources
PubMed1995

Primary structure of human amphiphysin, the dominant autoantigen of paraneoplastic stiff-man syndrome, and mapping of its gene (AMPH) to chromosome 7p13-p14.

Amphiphysin is a protein peripherally associated with synaptic vesicles. It is expressed in many neurons, certain endocrine cell types, and spermatocytes. Autoantibodies against amphiphysin occur in patients afflicted with a rare neurologic autoimmune disease, paraneoplastic Stiff-Man syndrome. To provide a basis for the understanding of anti-amphiphysin autoimmunity, we have cloned cDNAs and determined the primary structure of human amphiphysin. Comparison with chicken amphiphysin defines domains of low and high amino acid sequence conservation. As a candidate for heritable disorders of the nervous system, endocrine tissues or male fertility, the human amphiphysin gene was mapped to chromosome 7, region p13-p14.

Animals↗
PubMed1995

WASP gene mutations in Wiskott-Aldrich syndrome and X-linked thrombocytopenia.

The WASP gene has been recently cloned from Xp11.23 and shown to be mutated in three patients with the Wiskott-Aldrich syndrome (WAS). We have developed a screening protocol for identifying WASP gene alterations in genomic DNA and have identified a spectrum of novel mutations in 12 additional unrelated families. These missense, nonsense and frameshift mutations involve eight of the 12 exons of the gene. Two mutations creating premature termination codons were associated with lack of detectable mRNA on Northern blots. Four amino acid substitutions, Leu27Phe, Thr48Ile, Val75Met and Arg477Lys, were found in patients with congenital thrombocytopenia and no clinically evident immune defect indicating that the WASP gene is the site for mutations in X-linked thrombocytopenia as well as in WAS. A T-cell line from a WAS patient contained two independent DNA alterations, a constitutional frameshift mutation, also present in peripheral blood leukocytes from the patient, and compensatory splice site mutation unique to the cell line. The distribution of eight missense mutations provides valuable information on amino acids which are essential for normal protein function, and suggests that sites in the first two exons are hot-spots for mutation.

Adolescent↗
PubMed1995

Cloning and chromosomal localization of the human and murine genes for the T-cell transcription factors NFATc and NFATp.

The nuclear factor of activated T cells (NFAT) is a transcription factor complex involved in the activation of cytokines and cell surface molecules associated with coordinating the actions of different cells required for an immune response. Two different genes have recently been cloned that encode proteins capable of functioning as the pre-existing (p) and cytosolic (c) component of the NFAT transcription complex, NFATc of human and NFATp of murine origin (Northrop et al., 1994; McCaffrey et al., 1993b). We report here the partial cDNA cloning of the murine homolog of NFATc and the human homolog of NFATp, and the chromosomal localization of both genes in both species to conserved syntenic regions. Through the use of mapping panels of human x Chinese hamster and mouse x rodent cells hybrids, the NFATc genes were mapped to human and mouse chromosomes 18. By analyzing a chromosome 18 radiation hybrid panel, the human NFATc gene was localized to the q terminus, closely linked to STS marker D18S497. The murine Nfatc gene was sublocalized to chromosome band 18E4 by FISH. The NFATp genes were mapped by somatic cell hybrid analysis to human chromosome 20 and mouse chromosome 2. Human NFATp was assigned to chromosome region 20q13.2-->q13.3 by FISH. Based on the conserved syntenic region on human chromosome 20 and mouse chromosome 2, murine Nfatp is predicted to reside in the vicinity of a mutant locus wasted. Homozygous wst/wst mice display a phenotype reminiscent of severe combined immune deficiency or ataxia telangiectasia, disorders that could therefore be considered candidates for NFATp mutations.

Amino Acid Sequence↗
PubMed1995

Cloning and regional assignment of the human myosin heavy chain 12 (MYH12) gene to chromosome band 15q21.

Sequences encoding 1,235 bp of the human myosin heavy chain 12 (MYH12) gene have been cloned from a human brain cDNA library by PCR amplification. The human sequence is 95.8% identical to the mouse sequence at the amino acid level, indicating that the MYH12 gene has been evolutionarily well conserved. Somatic cell hybrid analysis and in situ hybridization place the MYH12 gene on human chromosome 15, at band q21, and extend distally the known region of chromosome 15 linkage homology on mouse chromosome 9.

Amino Acid Sequence↗
PubMed1995

Hemizygosity at the insulin-like growth factor I receptor (IGF1R) locus and growth failure in the ring chromosome 15 syndrome.

The ring chromosome 15 syndrome is characterized by mild-to-severe growth failure. We evaluated the status of the insulin-like growth factor I receptor (IGF1R) gene, which had previously been assigned to band 15q26 in several patients with de novo ring 15 chromosomes, to investigate a possible correlation between disruption or loss of the IGF1R gene with the severe growth failure phenotype. The presence or absence of the IGF1R gene on the ring 15 chromosomes of five patients was ascertained by in situ hybridization and gene-dosage (Southern) blotting. The location of the breakpoints was determined by typing polymorphic markers from the distal end of the long arm of chromosome 15 in both the probands and their parents. Deletion mapping determined that all breakpoints were distal to D15S100 and that the IGF1R gene is located between D15S107 and D15S87. Three patients who had suffered severe growth failure in early childhood were hemizygous at the IGF1R locus, while one patient with borderline short stature had two copies of the IGF1R gene. The correlation between IGF1R gene dosage and growth retardation demonstrated here in our ring chromosome 15 patients suggests a possible role for heterozygous IGF1R gene mutations or deletions in other cases of unexplained growth failure.

Abnormalities, Multiple↗
PubMed1995

The human calcitonin receptor gene (CALCR) at 7q21.3 is outside the deletion associated with the Williams syndrome.

The human calcitonin receptor (CTR) is a transmembrane peptide with dual action as a receptor for the hormone calcitonin and as an extracellular calcium sensor. Therefore, CTR dysfunction could lead to disorders of calcium metabolism associated with hypercalcemia, such as the Williams syndrome (WS). WS is a developmental disorder caused by a deletion at chromosome 7q11.23 that includes the elastin locus (ELN). We have mapped the CTR gene (CALCR) to chromosome band 7q21.3 by polymerase chain reaction and single-strand conformation analysis of somatic cell hybrids as well as fluorescence in situ hybridization (FISH) to metaphase chromosome spreads. Two-color FISH cohybridizing CTR and ELN probes confirmed that CALCR maps telomeric to ELN. Subsequent analysis of chromosome spreads from four WS patients revealed deletion of the ELN locus in all of them and normal hybridization of CTR probes to both chromosome 7 homologues, indicating that CALCR lies outside the deleted region.

Animals↗
PubMed1995

Mapping of synapsin II (SYN2) genes to human chromosome 3p and mouse chromosome 6 band F.

Synapsins are neuron-specific phosphoproteins of small synaptic vesicles encoded by two different genes. While the gene for synapsin I (SYN1) is on the X chromosome, we have now assigned the human and mouse synapsin II (SYN2) genes to autosomes. By using PCR primers derived from rat synapsin II cDNA sequences we were able to amplify homologous sequences of the 3'-untranslated regions and to localize the human SYN2 gene to 3p and the mouse Syn2 gene to mouse chromosome 6 by single strand conformation analysis of PCR products from panels of somatic hybrid cell lines. The mouse gene was further mapped by FISH to chromosome 6 band F in a region of known conserved synteny with human 3p. Genotyping of a M. musculus x M. spretus backcross panel placed Syn2 close to a cluster of previously mapped loci on chromosome 6 in an interval between interleukin 5 receptor alpha (Il5ra) and hematopoietic cell phosphatase 1C (Hcph). Both physical and genetic mapping data indicate that Syn2 is near two mutant loci defined by neuromuscular disorders, opisthotonus (opt) and deaf waddler (dfw).

Animals↗
PubMed1995

A Gly1127Ser mutation in an EGF-like domain of the fibrillin-1 gene is a risk factor for ascending aortic aneurysm and dissection.

Ascending aortic disease, ranging from mild aortic root enlargement to aneurysm and/or dissection, has been identified in 10 individuals of a kindred, none of whom had classical Marfan syndrome (MFS). Single-strand conformation analysis of the entire fibrillin-1 (FBN1) cDNA of an affected family member revealed a G-to-A transition at nucleotide 3379, predicting a Gly1127Ser substitution. The glycine in this position is highly conserved in EGF-like domains of FBN1 and other proteins. This mutation was present in 9 of 10 affected family members and in 1 young unaffected member but was not found in other unaffected members, in 168 chromosomes from normal controls, and in 188 chromosomes from other individuals with MFS or related phenotypes. FBN1 intragenic marker haplotypes ruled out the possibility that the other allele played a significant role in modulating the phenotype in this family. Pulse-chase studies revealed normal fibrillin synthesis but reduced fibrillin deposition into the extracellular matrix in cultured fibroblasts from a Gly1127Ser carrier. We postulate that the Gly1127Ser FBN1 mutation is responsible for reduced matrix deposition. We suggest that mutations such as this one may disrupt EGF-like domain folding less drastically than do substitutions of cysteine or of other amino acids important for calcium-binding that cause classical MFS. The Gly1127Ser mutation, therefore, produces a mild form of autosomal dominantly inherited weakness of elastic tissue, which predisposes to ascending aortic aneurysm and dissection later in life.

Adult↗
PubMed1995

Clinical and molecular cytogenetics and gene mapping: principles and techniques.

This article reviews the history of human cytogenetics with respect to technical advances from chromosome banding to molecular cytogenetics. Technologies such as in situ hybridization, chromosome painting, comparative genomic hybridization and interphase cytogenetics and their applications are discussed. The assignments of genes to chromosome regions by somatic cell genetics is illustrated by molecular analyses of somatic cell hybrid panels. The generation of complete physical maps of human chromosomes, by radiation hybrid mapping of sequence-tagged sites and establishment of chromosome-specific yeast artificial chromosome (YAC) banks and clone overlaps (contigs), is exemplified by studies of chromosome 18. The last section outlines the recent and future advances in clinical cytogenetics made possible by progress in molecular genetics.

Animals↗
PubMed1994

cDNA cloning of the human monocarboxylate transporter 1 and chromosomal localization of the SLC16A1 locus to 1p13.2-p12.

Lactate and pyruvate are transported across cell membranes by monocarboxylate transporters (MCTs). Here, we use the recently cloned cDNA for hamster MCT1 to isolate cDNA and genomic clones for human MCT1. Comparison of the human and hamster amino acid sequences revealed that the proteins are 86% identical. The gene for human MCT1 (gene symbol, SLC16A1) was localized to human chromosome bands 1p13.2-p12 by PCR analysis of panels of human x rodent cell hybrid lines and by fluorescence chromosomal in situ hybridization.

Amino Acid Sequence↗
PubMed1994

Isolation of a novel gene mutated in Wiskott-Aldrich syndrome.

Wiskott-Aldrich syndrome (WAS) is an X-linked recessive immunodeficiency characterized by eczema, thrombocytopenia, and recurrent infections. Linkage studies have placed the gene at Xp11.22-p11.23. We have isolated from this interval a novel gene, WASP, which is expressed in lymphocytes, spleen, and thymus. The gene is not expressed in two unrelated WAS patients, one of whom has a single base deletion that produces a frame shift and premature termination of translation. Two additional patients have been identified with point mutations that change the same arginine residue to either a histidine or a leucine. WASP encodes a 501 amino acid proline-rich protein that is likely to be a key regulator of lymphocyte and platelet function.

Amino Acid Sequence↗
PubMed1994

Structure and localization on the X chromosome of the gene coding for the human filopodial protein moesin (MSN).

Moesin is a member of a recently discovered family of closely related proteins that includes ezrin, radixin, and merlin. It is widely expressed in different tissues and cells and has been localized to filopodia and other membranous protrusions that are important for cell-cell recognition and signaling and cell movement. Here, we have localized the coding gene (MSN) to Xq11.2-q12 by Southern and Western blot analyses of Chinese hamster x human somatic cell hybrids and by fluorescence chromosomal in situ hybridization. Moesin-like sequences were identified on chromosomes 5 and 6. The murine Msn locus was mapped to the X chromosome as well by studying a rodent x mouse hybrid panel. The structure of the human moesin gene has been determined. The 12 exons are distributed over > 30 kb, and the exon/intron junctions demarcate individual highly conserved domains. Primer extension analysis revealed two major start transcription sites, 184 and 133 bp upstream of the initiation codon. The 5'-flanking region is GC-rich, lacks a TATA box, and contains four SP1 and one AP1 binding sites.

Animals↗
PubMed1994

Gene for a tissue-specific transcriptional activator (EBF or Olf-1), expressed in early B lymphocytes, adipocytes, and olfactory neurons, is located on human chromosome 5, band q34, and proximal mouse chromosome 11.

Murine B lymphocytes, adipocytes, and olfactory neurons contain a DNA-binding protein that participates in the regulation of genes encoding tissue-specific components of signal transduction. Purification and cloning of this protein, termed early B-cell factor (EBF), from murine B lymphocytes and independent cloning of a protein, termed Olf-1, from olfactory neuronal cells revealed virtual complete amino acid sequence identity between these proteins. As a first step towards identifying a human genetic disorder or mouse mutation for which EBF could be a candidate gene, we have chromosomally mapped the corresponding locus in both species. By Southern hybridization analyses of somatic cell hybrid panels with murine cDNA probe, fluorescence chromosomal in situ hybridization (FISH) of human genomic clones, and analysis of recombinant inbred mouse strains, we have found single sites for EBF homologous sequences on human Chromosome (Chr) 5, band q34, and on proximal mouse Chr 11, in an evolutionarily conserved region.

Adipocytes↗
PubMed1994

Chromosome localizations of genes for five cAMP-specific phosphodiesterases in man and mouse.

Cyclic nucleotides are important second messengers that mediate a number of cellular responses to external signals. Cyclic nucleotide phosphodiesterases play a role in signal transduction by regulating the cellular concentrations of these messengers. Here, we have applied Southern analyses of somatic cell hybrid lines and of recombinant inbred (RI) mouse strains as well as fluorescence chromosomal in situ hybridization (FISH) to chromosomally localize five cAMP-specific nucleotide phosphodiesterase genes in human and mouse. Genes DPDE1, DPDE2, DPDE3, and DPDE4 that share sequence homology with the Drosophila dunce gene were assigned to human chromosome 19 (DPDE1 and DPDE2), 5q12 (DPDE3), and 1p31 (DPDE4) and to mouse chromosomes 8, 9, 13, and 4, respectively. The high-affinity cAMP-specific phosphodiesterase gene (HCP1) was mapped to human chromosome 8q13-q22. Since these genes are potential candidates for involvement in psychiatric or behavioral disorders, knowledge of their chromosomal localizations will facilitate the discovery of their association with disease genes as they are being mapped by linkage studies.

3',5'-Cyclic-AMP Phosphodiesterases↗