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T Liehr

Publications and source records attributed to T Liehr.

At least 73 records · Page 4Linked to original sources
PubMed2001

Detection of microdeletions in the short arm of the X chromosome by chromosome stretching.

The present study was focused on the resolution of "chromosome stretching". In order to determine if this method can be used for the detection of microdeletions, the p-arms of 13 normal X chromosomes were stretched as well as of those with three different deletions of known size within the DMD/BMD region in Xp21 (case A: 0.42-0.45 Mb, case B: 2.3-2.9 Mb and case C: 3.0-3.5 Mb). The process of band splitting was recorded on a video-tape and the resulting banding pattern analyzed. Stretching of the normal Xp-arms led to a splitting on a maximum band level of 1400 and showed in all cases an identical banding pattern with 13 Giemsa-dark subbands. All new Giemsa-dark and -light subbands were derived from the three initial Giemsa-dark bands at the 400 band level according to ISCN (1995): five subbands from Xp21, four subbands from Xp11.3 and Xp22.2, respectively. The origin of these subbands is partly in contrast to the high resolution ISCN (1995) ideograms: subband Xp11.22 does not originate from the Giemsa-light band Xp11.2, but from the Giemsa-dark band Xp11.3; Xp22.12 originates from Xp21; Xp22.32 from Xp22.2. Stretching of the chromosomes containing deletions showed in cases A and B no differences in banding patterns and splitting order compared to normal X chromosomes. Only in patient C was a significant difference with the normal pattern visible due to the absence of one dark subband. In this case only four Giemsa-dark subbands derived from band Xp21. Thus, at least in the DMD/BMD region, the minimal size of a deletion detected by chromosome-stretching-generated high-resolution ideograms is about 3.0-3.5 Mb.

Azure Stains↗
PubMed2001

A long distance-PCR derived FISH probe detects a deletion between p15 and p16 in CML and T-ALL patients.

The tumor suppressor genes p15INK4B and p16INK4A, located in the chromosomal region 9p21, are frequently inactivated by homo- or hemizygous deletions, point mutation or promotor methylation in various types of cancer. No commercial probe is yet available that allows the detection of such deletions by FISH. Long distance (LD)-PCR was successfully used to generate a FISH probe, that covers a sequence stretch of 11.68 kb, located between the tumor suppressor genes p15 and p16. The LD-PCR amplicon was cloned and biotinylated by DOP-PCR (degenerated oligonucleotide primed-PCR) or nick translation. The FISH probe was hybridized on different samples of 16 patients with leukemia (3 T-ALL, 13 CML) and normal controls. Loss of at least one FISH-signal was found in 2/3 (67%) of the T-ALL- and 2/13 (15%) of the CML-cases. The new FISH probe presented here was proven to be advantageous for the detection of deletions in chromosomal region 9p21, especially between p15 and p16.

Adolescent↗
PubMed2001

Expression analysis and chromosome location of a novel gene (H11) associated with the growth of human melanoma cells.

We have previously described the isolation of a new human gene, H11, that codes for a 25 kDa phosphoprotein with autokinase activity the expression of which is required for cell growth. The data described in this report extend these findings. Using FISH and M-FISH we show that H11 which maps at chromosome site 12q24.1-12q24.31 is not involved in chromosomal translocations. The tissue distribution of H11 mRNA is restricted, with expression being most abundant in skeletal muscle, heart, prostate and placenta. The H11 protein is cytoplasmic and it is associated with the plasma membrane. Cell surface localization in particulate aggregate formations suggests that it may be complexed to proteins involved in the transfer of extracellular growth signals.

Blotting, Northern↗
PubMed2000

Structure and chromosomal localization of the human and mouse muscle fructose-1,6-bisphosphatase genes.

Mammalian skeletal muscle contains fructose-1,6-bisphosphatase (Fru-1,6-P(2)ase), a key enzyme of glyconeogenesis. We have shown previously that muscle Fru-1,6-P(2)ase is encoded by a gene different from that coding for the liver isoenzyme. Starting with genomic YAC libraries and based on the cDNA sequences of human and mouse muscle Fru-1,6-P(2)ases together with the known gene structures of two mammalian liver fructose-1,6-bisphosphatases, we have PCR-amplified and sequenced all functional parts of the human and mouse muscle fructose-1,6-bisphosphatase genes and determined their chromosomal localization. The human gene (FBP2), localized at chromosome 1p36.1-2, spans about 30 kb, while the mouse gene (Fbp2) at chromosome 13B3-C1 is more compact (about 21 kb). Intron lengths are only poorly conserved between the two genes, while intron number and positions are identical in all hitherto analyzed mammalian fructose-1,6-bisphosphatase isoenzyme genes. Transcriptional start sites were found to be located 97 and 95bp before the start codon in the human gene and 35 bp before the start codon in the mouse homolog. A comparison of the 5'-flanking sequences of the two genes revealed a 56% homology up to human bp -607 before the first transcriptional start point, while upstream of this region we found no similarity. The data presented in this paper provide a basis for further studies of the mechanism of expression regulation and the elucidation of the physiological role of the enzyme.

Animals↗
PubMed2000

Incidental prenatal detection of an Xp deletion using an anonymous primer pair for fetal sexing.

We report on the incidental prenatal detection of an interstitial X-chromosomal deletion in a male fetus and his mother by fetal sexing with a primer pair recognizing an X-Y homologous locus (DXYS19), formerly unassigned on the X chromosome. The proband asked for prenatal diagnosis because of her elevated age and risk of Duchenne muscular dystrophy (DMD). Prior to molecular genetic testing for DMD, fetal sexing was carried out on DNA prepared from cultured amniocytes. PCR analysis revealed the expected Y-chromosomal product, but did not show the constitutive X-chromosomal fragment. The absence of the X-chromosomal fragment in the fetus and on one X chromosome of the mother was confirmed by Southern hybridization of HindIII restricted DNA with probe pJA1165 (DXYS19). DXYS19X was mapped to Xp22.3 by combining several approaches, including: (1) analysis of somatic cell hybrid lines containing different fragments of the human X chromosome; (2) Southern hybridization of a yeast artificial chromosome (YAC)-filter panel provided by the Resource Center/Primary Database (RZPD); (3) FISH analysis; and (4) re-evaluation of two patients with interstitial deletions in Xp22.3. The extent of the deletion in the fetus was estimated by further markers from Xp22.3 and found to include the STS gene. Mental retardation could not be excluded since some mentally retarded patients exhibit overlapping deletions.

Adult↗
PubMed2000

An essential SMN interacting protein (SIP1) is not involved in the phenotypic variability of spinal muscular atrophy (SMA).

The survival motor neuron (SMN) protein and the SMN interacting protein 1 (SIP1) are part of a 300 kD protein complex with a crucial role in snRNP biogenesis and pre-mRNA splicing. Both proteins are colocalised in nuclear structures called gems and in the cytoplasm. Approximately 96% of patients with autosomal recessive spinal muscular atrophy (SMA) show mutations in the SMN1 gene, while about 4% fail to show any mutation, despite a typical SMA phenotype. Additionally, sibs with identical 5q13 homologs and homozygous absence of SMN1 can show variable phenotypes which suggest that SMA is modified by other, yet unknown factors. Since both genes, SMN1 and SIP1, belong to the same pathway and are part of the same protein complex, it is obvious to ask whether mutations within SIP1 are responsible for both the phenotypic variability and the appearance of non-SMN mutated SMA patients. First, we identified the chromosomal location of SIP1 and assigned it to chromosomal region 14q13-q21 by fluorescence in situ hybridisation. No SMA related disorder has yet been assigned to this chromosomal region. Next, we determined the exon-intron structure of the SIP1 gene which encompasses 10 exons and identified five transcription isoforms. We sequenced either RT-PCR products or genomic DNA covering the complete coding region from 23 typical SMA patients who had failed to show any SMN1 mutation. No mutation and no polymorphism was found within SIP1. Additionally, we sequenced RT-PCR products or genomic fragments of the entire SIP1 coding region from 26 sibs of 11 SMA families with identical genotypes (delta7SMN/delta7SMN or delta7SMN/other mutation) but different phenotypes and again no mutation was found. Finally, we performed quantitative analysis of RT-PCR products from the same 26 sibs. No difference in expression level of the five isoforms among phenotypically variable sibs was observed. Based on these data, we suggest that neither the phenotypic variability nor the 5q-unlinked SMA are caused by mutations within SIP1.

Alternative Splicing↗
PubMed2000

Molecular cytogenetic characterisation of partial trisomy 9q in a case with pyloric stenosis and a review.

Partial trisomy 9q represents a rare and heterogeneous group of chromosomal aberrations characterised by various clinical features including pyloric stenosis. Here, we describe the case of a 1 year old female patient with different dysmorphic features including pyloric stenosis and prenatally detected partial trisomy 9q. This partial trisomy 9q has been analysed in detail to determine the size of the duplication and to characterise the chromosomal breakpoints. According to the data gained by different molecular cytogenetic techniques, such as fluorescence in situ hybridisation (FISH) with whole and partial chromosome painting probes, yeast artificial chromosome (YAC) probes, and comparative genomic hybridisation (CGH), the derivative chromosome 9 can be described as dup(9)(pter-->q22. 1::q31.1-->q22.1::q31.1--> q22.1::q31.1-->qter). Four breakpoint spanning YACs have been identified (y806f02, y906g6, y945f5, and y747b3) for the proximal breakpoint. According to this new case and previously published data, the recently postulated putative critical region for pyloric stenosis can be narrowed down to the subbands 9q22.1-q31.1 and is the result of either partial trisomy of gene(s) located in this region or a gene disrupted in 9q31.

Chromosome Banding↗
PubMed2000

Zoo-FISH with region-specific paints for mink chromosome 5q: delineation of inter- and intrachromosomal rearrangements in human, pig, and fox.

Comparison of evolutionarily conserved mammalian chromosomes homologous to human chromosome 17, performed with microdissected painting probes, revealed rearrangements inside these chromosomes in mink and pig and a disruption of this conserved region in the fox. Detection of a homologous region on an Iberian shrew chromosome showed the efficiency of microdissected painting probes for delineation of homologous chromosome regions in species belonging to orders that diverged at least 100 million years ago.

Animals↗
PubMed2000

Microdeletion 4p16.3 in three unrelated patients with Wolf-Hirschhorn syndrome.

Wolf-Hirschhorn syndrome (WHS) is a multiple malformation syndrome caused by partial monosomy of 4p16.3. Pitt-Rogers-Danks syndrome, first thought to be a distinct entity, is a similar condition associated with a microdeletion overlapping the WHS critical region. In this paper we evaluate three WHS patients showing a microdeletion of 4p and remarkable development with respect to the clinical spectrum of WHS.

Abnormalities, Multiple↗
PubMed2000

Insulin-like growth factor serum concentrations reflect insufficient growth in a hypoplastic infant with partial trisomy 9q in the 12th week of life.

This report presents changes of IGFs and IGFBPs in a female infant with partial trisomy 9q in the 12th week of life. Studying deficient growth in this hypoplastic infant (birth weight 1405 g, birth length 36 cm) with dysmorphic features, the following changes in IGFs and IGFBPs were detected (microg/l): IGF-I: 26.5 vs 48.1 in healthy infants; IGF-II: 420 vs 728; IGFBP-2: 931 vs 524; IGFBP-3: 800 vs 1070. This demonstrates that IGFs and IGFBPs may reflect individual insufficient growth even at this early age.

Adult↗
PubMed2000

Patterns of genomic imbalances in human solid tumors (Review).

Based on comparative studies on CGH-detected genomic imbalances in head and neck squamous cell carcinomas and in ovarian tumors it was supposed that the patterns of genomic imbalances in human tumors are not only related to the oncogenic progress and tumor progression or specific for the tissue of origin, but also could be influenced by environmental (mutagenic) factors present in the environment of the evolving cancer. To base this hypothesis on a more solid ground, data obtained by use of comparative genomic hybridization (CGH) which were reported up to early 1999 from a large variety of more than 2400 human solid tumors, representing 18 different organs of origin or physical localizations, were collected and comparatively analyzed. Patterns of inter- and intra-chromosomal distribution of DNA sequence copy number changes pointed to high conformity on several chromosomal segments, but also revealed striking differences between the tumor types, the latter suggesting tumor specific, tissue specific and/or environment specific influences on the generation of genomic imbalance in human neoplasia. The clinical relevance of these findings must be examined further on by increasing the studied material.

Chromosome Banding↗
PubMed2000

Microdissection based comparative genomic hybridization analysis (micro-CGH) of secondary acute myelogenous leukemias.

Comparative genomic hybridization (CGH) is a well established technique in molecular cytogenetics. However, leukemias, and especially secondary acute myelogenous leukemias (sAML) are not very well analyzed by this technique, even though such diseases are often characterized by complex karyotypic changes, not resolvable by conventional cytogenetic banding analysis. This lack of CGH-studies might be due to the fact, that in most cases bone marrow aspirate is too limited to do DNA-extraction additionally to the cytogenetic analysis. To circumvent this problem a new CGH technique has been applied to analyze 10 AML cases with complex karyotypic changes. In each case 15 interphase nuclei of the harvested and fixed bone marrow cell-suspension have been microdissected from the coverslip surface and collected in a tube. Subsequently, DNA was amplified by DOP-PCR. With this micro-CGH technique additional cytogenetic information from 10 highly aberrant AML cases was obtained and confirmed by FISH on metaphase of the corresponding AML case.

Aged↗
PubMed1999

Expression analysis of the PMP22 gene in glioma and osteogenic sarcoma cell lines.

Previously we reported the amplification of the peripheral myelin protein 22 (PMP22) gene in cell lines of human osteogenic and glioma tumors. PMP22 normally is expressed at high levels in Schwann cells of the peripheral nervous system and is suggested to function as a structural protein of the myelin sheath. One of the most common inherited peripheral neuropathies, Charcot-Marie-Tooth Type 1A (CMT1A), is associated with a duplication of a 1.5-Mb DNA region on chromosome 17p11.2 - p12 containing PMP22. On the other hand, PMP22 is identical to gas3, whose expression is induced in growth-arresting NIH3T3-fibroblasts and is thought to play a role in cell proliferation. The precise role of gas3/PMP22 remains to be determined. Here we show that in the tumor cell lines RH30 and SF763 the amplified region including PMP22 comprises the whole 1.5-Mb CMT1A region. We could prove expression of PMP22 by reverse transcriptase-polymerase chain reaction (RT-PCR) and discovered an unusual PMP22 transcript in these tumor cell lines. Western blot analyses resulted in detection of a 22-kDa protein by the PMP22-specific antibody 558/2 and in exclusion of myelin protein zero (MPZ) expression in these cell lines.

Amino Acid Sequence↗
PubMed1999

Nucleus extraction from single mounted tissue sections.

Extraction of nuclei from unmounted archived tissue has become a method widely used for molecular cytogenetic investigations. It is a suitable approach to take advantage of the large series of formalin fixed and subsequently paraffin-embedded material which has been collected in the times before interphase cytogenetic analysis has become possible. We present a new kind of assay for the extraction of nuclei from one single mounted tissue section; the extracted interphase nuclei are suitable very well for a fluorescence in situ hybridization (FISH) approach. The method described has been successfully used for the analysis of the INT2/FGF3-amplicon in 20 samples of oral squamous cell carcinoma.

Carcinoma, Squamous Cell↗
PubMed1999

Localization of mariner DNA transposons in the human genome by PRINS.

Homologous recombination occurring among misaligned repeated sequences is a significant source of the molecular rearrangements resulting in human genetic disease. Studies of the Charcot-Marie-Tooth disease locus on chromosome 17 have implicated the involvement of an ancient DNA transposon of the mariner family (Hsmar2) in the initiation of double-strand break events leading to homologous recombination. In this study, the genomic locations of 109 Hsmar2 elements were determined by primed in situ labeling (PRINS) using primers designed to match the right and left inverted terminal repeats (ITRs) of the transposon. Although the resolution of the PRINS technique is approximately 400 chromosomal Giemsa bands, the data presented here provide the first large-scale mapping study of these elements, which may be involved in initiation of homologous recombination events in the human genome.

Chromosome Mapping↗