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N Blin

Publications and source records attributed to N Blin.

At least 109 records · Page 6Linked to original sources
PubMed1991

The codon 408 mutation associated with haplotype 2 is predominant in Polish families with phenylketonuria.

The incidence of phenylketonuria (PKU) in the western part of Poland is 1 in 5000 live births. Restriction fragment length polymorphism (RFLP) haplotypes at the phenylalanine hydroxylase locus have been analysed in 46 Polish families with PKU. Among 43 fully-informative families 16 RFLP haplotypes were identified. Haplotype 2 is the most frequently (62%) associated with Polish PKU alleles, and the codon 408 mutation is in complete linkage disequilibrium with this haplotype in Poland. This finding is in agreement with observations in other eastern European countries (German Democratic Republic, Czechoslovakia, and Hungary) and in contrast to the genotype distribution observed in western European countries. The present observation suggests the spread of classical PKU, due to the codon 408 mutation associated with haplotype 2, from east to west in European populations. Perhaps more important for genetic counselling, 62% of all PKU chromosomes in the Polish population can now be detected using only one mutant-specific oligonucleotide probe.

Alleles↗
PubMed1991

A set of 4 nuclear proteins binds to a DNA sequence within the FOS promoter region.

We investigated DNA-protein-interactions occurring in the promoter region of c-fos using two-dimensional electrophoresis and south-western-blotting. When nuclear extracts from the human glioblastoma cell line HeRoSV were tested for their DNA-binding behaviour to a 650 bp-fragment within the promoter region of c-fos, we found 4 proteins designated as 120/6.6, 75/5.4, 65/6.4 55/5.0 interacting with this fragment. An additional protein 60/6.0 was detected by using a digoxygenine-labelled probe. These observations let us to assume that beside the well characterized SRF and FOS-JUN proteins additional factors recognize the promoter sequence and may play a role in c-fos regulation.

Base Sequence↗
PubMed1991

Expression of the breast cancer associated gene pS2 and the pancreatic spasmolytic polypeptide gene (hSP) in diffuse type of stomach carcinoma.

Expression of the pancreatic spasmolytic peptide (hSP) gene and pS2 (a gene isolated from oestrogen-induced breast carcinoma cells) were analysed in 36 samples of human stomach carcinoma. 17 tumours were investigated at the RNA level (by northern blots) as well as at the gene product level (by immunochemistry). Since pS2 had been shown to be expressed in normal stomach mucosa its activity in carcinoma samples was expected. Surprisingly, strong pS2 immunoreactivity was noted in the diffuse carcinoma type, whereas the intestinal type displayed weak reactivity. The tumour samples showing strong immunostaining expressed the regular 0.6 kb pS2 RNA band and weak staining was paralleled by aberrant transcripts. Additionally, only in tumour samples with regular pS2 transcription was the typical 0.7 kb hSP RNA band seen; samples with aberrant pS2 bands did not express hSP at all. This is the first demonstration of hSP gene activity in a human tumour.

Blotting, Northern↗
PubMed1991

Large-scale physical mapping within the region 22q12.3-13.1 in meningioma.

The lack of physical mapping data strongly restricts the analysis of the meningioma chromosomal region that was assigned to the bands 22q12.3-qter. Recently, we reported a new marker D22S16 for chromosome 22 that was assigned to the region 22q13-qter by in situ hybridization. Utilizing somatic cell hybrids we now sublocalized the marker D22S16 within the band region 22q12-13.1, thus placing it in the vicinity of the gene for the platelet derived growth factor (PDGFB). A physical map was established for the regions surrounding the PDGFB gene and the D22S16 marker. By means of pulsed-field gel electrophoresis (PFGE) D22S16 and PDGFB were found to be physically linked within 900 kb. We also identified two CpG clusters bordering the PDGFB gene. For the enzyme NotI, a variation of the PDGFB restriction pattern was found between different individuals. PFGE analysis of the two loci (PDFGB and D22S16) failed to identify major rearrangements in meningioma.

Animals↗
PubMed1991

Loss of heterozygosity on chromosome 3, bands q24----qter, in a diploid meningioma.

Cytogenetic analysis of a meningioma from a 46-year-old female patient exhibited as the sole cytogenetic aberration a deletion on the long arm of one chromosome 3 involving bands 3q24----qter. To verify this finding, RFLP analysis was performed with two polymorphic probes, MOX2 and D3S5. The patient was informative for both single copy probes and demonstrated loss of heterozygosity in the region above whereas chromosome 22 displayed no loss of heterozygosity as judged by a proximal and a distal probe.

Chromosome Banding↗
PubMed1991

Breast cancer-associated protein pS2 expression in tumors of the biliary tract.

Expression of pS2 (an estrogen-induced gene isolated from breast carcinoma MCF7 cells) and of the human spasmolytic peptide (hSP) gene was analyzed in 21 human biliary tract and gallbladder carcinomas and 16 non-neoplastic gallbladders at the protein level (immunochemistry) and, in a series of these cases, at the RNA level (Northern blots). Eighteen carcinomas and 14 non-neoplastic mucosae with inflammatory alterations showed pS2 activity by immunostaining or Northern blotting. In addition, in samples with pS2 expression, hSP RNA was demonstrated. In the corresponding non-neoplastic and healthy mucosae, pS2 was negative, as judged by immunostaining. Northern blots showed weak (basal) level of activity for pS2 and hSP. The genes' increased expression in correlation to inflammatory and neoplastic processes, by now observed in several carcinomas and idiopathic inflammatory bowel disease, hints to their essential role in such diseases.

Biliary Tract Neoplasms↗
PubMed1990

The cellular myb oncogene is amplified, rearranged and activated in human glioblastoma cell lines.

The human c-myb gene which encodes a DNA binding protein and which is rarely amplified in neoplastic cells was found to be altered in four human glioblastoma cell lines. It exists in multiple copies in 2 out of 4 cases studied. The degree of amplification as determined by densitometry was about 10-fold, a rearrangement within the coding region and an enhanced gene activity of c-myb were noted. The observation of c-myb oncogene amplification and activity in glioblastoma cell lines presents the first report of this effect in human brain tumor cells.

Brain Neoplasms↗
PubMed1990

Generating highly labeled oligonucleotides for DNA-protein interaction.

We developed a new strategy to prepare double-stranded oligonucleotides containing recognition sites for specific binding proteins to examine DNA-protein interactions in various assays (gel mobility shift, UV-crosslinking, and affinity chromatography). The advantages of our procedures are as follows. Only one strand needs to be synthesized using a commercial oligonucleotide synthesizer. The probes can be labeled to a high specific activity and the exact position of labeling can be chosen, which is necessary for UV-crosslinking studies. Furthermore, multimeric binding sites for efficient DNA affinity chromatography can easily be generated. It is also possible to precisely place modified bases without the need for chemical precursors. Using this protocol, more detailed information about the binding protein factors and their behavior in interaction with recognition sites can be obtained.

Base Sequence↗
PubMed1990

Localization of 27 DNA markers to the region of human chromosome 22q11-pter deleted in patients with the DiGeorge syndrome and duplicated in the der22 syndrome.

DiGeorge syndrome is a human developmental field defect with the pathological features of an abnormality of embryogenesis at 4 to 6 weeks of gestation. Cytogenetic analyses of patients have revealed a number of instances of monosomy 22q11-pter in this condition. We have analyzed 52 DNA markers that map to 22q11-pter and have found 27 that are deleted in DiGeorge syndrome patients with known monosomy for part of this region and that are duplicated in patients with the der22 syndrome. The set of clones mapping to the DiGeorge region was further assigned to a proximal or a distal location within the deletion.

Base Sequence↗
PubMed1990

Isolation and characterization of DNA sequences from flow-sorted human chromosome 22 libraries.

Two flow-sorted chromosome 22 libraries were used to isolate DNA sequences specific for chromosome 22. 45-phage DNAs were probed against human genomic DNA. 12 of them showed unique or low-copy character. Using digested DNA from rodent-human hybrid cell lines, 3 of the 12 recombinants were assigned unique to chromosome 22 and regionally mapped. 1 clone mapped to 22pter-q11, 1 clone to 22q12-qter and 1 clone, for which in situ hybridization was performed, to 22q13.1. 2 low-copy probes, 1 of them displaying polymorphisms in MspI and TaqI digests of individual DNAs, must have similar sequences on 22 and additional chromosomes. Furthermore, a highly repetitive DNA representing a compound locus of some hundred kilobases on chromosome 22 was isolated. These 6 probes may provide useful tools for studying the structure and function of this small chromosome involved in a relatively high number of inherited and acquired diseases.

Chromosomes, Human, Pair 22↗
PubMed1989

A rapid protocol for the purification of mitochondrial DNA suitable for studying restriction fragment length polymorphisms.

When analyzing mitochondrial DNA (mtDNA) from various normal and malignant human tissues, it became necessary to enhance mtDNA isolation for improved yields and quality. The method described here consists of rapid and simple-to-perform steps, avoiding complicated instrumentation. It was designed for preparation of undegraded mtDNA and is highly useful when limited amounts of tissues, cells and unique biopsies of tumors (fresh or frozen) are available. The resulting mtDNA is sufficiently pure for restriction analysis, subcloning, labeling and various types of hybridization. Using Sau3A and MspI, restriction analysis revealed new restriction-fragment length polymorphisms for Caucasians, independent of the DNA source, and hence excluding tissue-specific DNA modifications.

Centrifugation↗
PubMed1989

DNA curvature in front of the human mitochondrial L-strand replication origin with specific protein binding.

DNA bending has been suggested to play a role in the regulation of gene expression, initiation of DNA-replication, site specific recombination, and DNA packaging. In the human mitochondrial DNA we have found a DNA curvature structure within the 3'-region of ther URF2 sequence in front of the L-strand origin of replication. This structure interacts specifically with a protein factor isolated from mitochondria. Based on the localization of this DNA curvature structure and the known function of such structures the data suggest a model in which this DNA signal sequence and its specific protein binding is involved in the regulatory initiation event of L-strand replication.

Base Sequence↗
PubMed1989

Alteration of mitochondrial DNA in human oncocytomas.

Oncocytoma, a benign solid tumor, occurs in a number of organs but most frequently in the kidneys. Its oncocytes display an intensely eosinophilic cytoplasm due to presence of numerous mitochondria. Mitochondrial DNA analysis of six renal cell oncocytomas and adjacent renal tissue was performed using five restriction endonucleases. In the Hinfl restriction pattern, an additional 40 bp band was noted. This new band was demonstrated in all oncocytomas but in none of the corresponding renal tissues or additionally tested renal carcinomas. By reisolating and hybridizing this band to the mitochondrial genome, its sequence was localized within the cytochrome c oxidase subunit I gene. The data suggest that a molecular alteration of mitochondrial DNA is specific for oncocytomas, and this constitutes the first observed mitochondrial DNA change in a human solid tumor.

Adenoma↗
PubMed1989

Regional localization and molecular characterization of a DNA sequence on the long arm of chromosome 22.

A human genomic DNA fragment, p22hom13 (D22S16), was isolated from a chromosome 22-specific library. After elimination of repetitive sequences, a single copy BamHI-EcoRI fragment was subcloned into pTZ18. By using mouse/human somatic cell hybrids and in situ hybridization, the new DNA probe was mapped to chromosome 22q13-qter. Its application in the analysis of the distal part of chromosome 22 and its diagnostic use in translocations are discussed.

Chromosome Mapping↗