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Biomedical subjects

J Kere

Publications and source records attributed to J Kere.

At least 19 recordsLinked to original sources
PubMed1992

Evidence that the MCC-APC gene region in 5q21 is not the site for susceptibility to hereditary nonpolyposis colorectal carcinoma.

Hereditary nonpolyposis colorectal carcinoma (HNPCC) is the most common form of hereditary colon cancer. Autosomal dominant inheritance is evident from pedigrees but the genetic basis of the disorder is otherwise unknown. Recently, two genes in 5q21 involved in colon carcinogenesis, APC and MCC, were identified, and APC was shown to be the gene predisposing to familial adenomatous polyposis. To determine if these genes also confer susceptibility to HNPCC we performed linkage analyses in nine affected families. The MCC-APC region could be formally excluded as the locus for HNPCC in seven families. In one family the results were suggestive of exclusion, although they were not conclusive. The remaining family was uninformative. We used two alternative definitions of affected status. Based on haplotypes for MCC and APC the added pairwise logarithm-of-odds score for all nine families was -22.57 at the recombination fraction of 0.00 using more stringent criteria for the HNPCC phenotype and -22.67 for less stringent criteria. In addition to blood DNA samples from living family members, DNA from formaldehyde-fixed archival pathology specimens from decreased individuals contributed to these linkage results.

Base Sequence↗
PubMed1992

Conserved sequence-tagged sites: a phylogenetic approach to genome mapping.

Cognate sites in genomes that diverged approximately 100 million years ago can be detected by PCR assays based on primer pairs from unique sequences. The great majority of such syntenically equivalent sequence-tagged sites (STSs) from human DNA can be used to assemble and format corresponding maps for other primates, and some based on gene sequences are shown to be useful for mouse and rat as well. Universal genomic mapping strategies may be possible by using sets of STSs common to many mammalian species.

Animals↗
PubMed1992

Abnormalities of chromosomes 7 and 22 in human malignant pleural mesothelioma: correlation between Southern blot and cytogenetic analyses.

Southern blot hybridization studies were performed on 23 mesothelioma primary tumor specimens to detect chromosome 1-, 7-, and 22-specific numerical changes, gene amplifications, and gene rearrangements. The molecular findings were compared with previous cytogenetic findings. No gene rearrangements or amplifications were detected. A numerical abnormality of chromosome 7 was detected by Southern blot analysis in two cases in which no numerical abnormality had been detected by the previous chromosome study. A numerical aberration of chromosome 22 was detected in five cases, which was compatible with the cytogenetic finding of monosomy 22 in these cases. The Southern blot results for the copy numbers of chromosomes 7 and 22 were concordant with the cytogenetic findings in 65%-80% of the cases.

Blotting, Southern↗
PubMed1992

Familial amyloidosis, Finnish type: G654----a mutation of the gelsolin gene in Finnish families and an unrelated American family.

The Finnish type of familial amyloid polyneuropathy (FAF) is an autosomal dominant form of systemic amyloidosis caused by a mutation in the gelsolin gene. The mutation leads to the expression of amyloidogenic mutant Asp187----Asn gelsolin, an actin-modulating protein. We previously developed a DNA test based on amplification by the polymerase chain reaction followed by allele-specific oligonucleotide hybridization that identifies the base substitution adenine for guanine at nucleotide 654 in the gelsolin gene causing the disease. We show here that the same mutation is present in members of six apparently unrelated Finnish families and in a member of an unrelated American family. These results, taken together with previously published findings in nine additional Finnish families and another unrelated American family, indicate that most, perhaps all, FAF patients in Finland and possibly worldwide carry the same mutation. We suggest two alternative explanations: (i) the mutation arose in a very early common ancestor or (ii) the Asn187 mutation is particularly, perhaps uniquely, amyloidogenic.

Amino Acid Sequence↗
PubMed1992

Mapping human chromosomes by walking with sequence-tagged sites from end fragments of yeast artificial chromosome inserts.

Sequence-tagged sites (STSs) derived from end fragments of chromosome-specific yeast artificial chromosomes (YACs) can facilitate the assembly of an overlapping YAC/STS map. Contigs form rapidly by iteratively screening YAC collections with end-fragment STSs from YACs that have not yet been detected by any previous STS. The map is rendered rapidly useful during its assembly by incorporating supplementary STSs from genes and genetic linkage probes with known locations. Methods for the systematic development and testing of the end-fragments STSs are given here, and a group of 100 STSs is presented for the X chromosome. The mapping strategy is shown to be successful in simulations with portions of the X chromosome already largely mapped into overlapping YACs by other means.

Base Sequence↗
PubMed1992

Gelsolin-derived familial amyloidosis caused by asparagine or tyrosine substitution for aspartic acid at residue 187.

Dominantly inherited familial amyloidosis, Finnish type (FAF) is caused by the accumulation of a 71-amino acid amyloidogenic fragment of mutant gelsolin (GSN). FAF is common in Finland but is very rare elsewhere. In Finland and in two American families, the mutation is a G654A transition leading to an Asp to Asn substitution at residue 187. We found the same mutation in a Dutch family but a Danish FAF family had a G654T mutation, predicting Asp to Tyr at residue 187. We also found the G654T transversion in a Czech family. Using GSN polymorphisms, different haplotypes were found in the Danish and Czech families. We conclude that substitution of the uncharged Asn or Tyr for the acidic Asp at residue 187 creates a conformation that may be preferentially amyloidogenic for GSN.

Alleles↗
PubMed1992

Simplified template preparation and improved direct sequencing using Taq polymerase.

A streamlined version of direct dideoxy sequencing is presented that includes template preparation as well as sequencing protocols. The method is used routinely to sequence double-stranded PCR products after minimal purification with one of the primers used in amplification. Either 35S or 32P labeling can be used with equally good results.

DNA-Directed DNA Polymerase↗
PubMed1992

Screening for defined cystic fibrosis mutations by solid-phase minisequencing.

We have developed a rapid method for the quantitative detection of point mutations and deletions. In this minisequencing method, enzymatically amplified DNA, 5'-biotinylated in one strand, is bound to a solid phase and denatured. A detection primer, constructed to end immediately before the mutation, is annealed to the immobilized single-stranded template and elongated with a single, labeled deoxynucleoside residue. We have applied the solid-phase minisequencing method to the detection of the major mutation, delta F508, causing cystic fibrosis (CF). In the presence of the allele with the delta F508 mutation, [3H]dTTP is incorporated; with the nonmutated allele, [3H]dCTP is incorporated. Thus, samples from heterozygous individuals allow the incorporation of both labels. The method was evaluated by analyzing 59 coded DNA specimens collected from 20 Finnish CF patients and their parents. The ratio of [3H]C to [3H]T gave unambiguously the allele combination. The solid-phase minisequencing method was also applicable to the analysis of three CF mutations simultaneously, i.e., delta F508, G542X, and G551D. We conclude that the microtiter-plate-based minisequencing test is an accurate method for the screening of defined sequence alterations in the CF gene.

Base Sequence↗
PubMed1991

Direct selection: a method for the isolation of cDNAs encoded by large genomic regions.

We have developed a strategy for the rapid enrichment and identification of cDNAs encoded by large genomic regions. The basis of this "direct selection" scheme is the hybridization of an entire library of cDNAs to an immobilized genomic clone. Nonspecific hybrids are eliminated and selected cDNAs are eluted. These molecules are then amplified and are either cloned or subjected to further selection/amplification cycles. This scheme was tested using a 550-kilobase yeast artificial chromosome clone that contains the EPO gene. Using this clone and a fetal kidney cDNA library, we have achieved a 1000-fold enrichment of EPO cDNAs in one cycle of enrichment. More significantly, we have further investigated one of the "anonymous" cDNAs that was selectively enriched. We confirmed that this cDNA was encoded by the yeast artificial chromosome. Its frequency in the starting library was 1 in 1 x 10(5) cDNAs and after selection comprised 2% of the selected library. DNA sequence analysis of this cDNA and of the yeast artificial chromosome clone revealed that this gene encodes the beta 2 subunit of the human guanine nucleotide-binding regulatory proteins. Restriction mapping and hybridization data position this gene (GNB2) to within 30-70 kilobases of the EPO gene. The selective isolation and mapping of GNB2 confirms the feasibility of this direct selection strategy and suggests that it will be useful for the rapid isolation of cDNAs, including disease-related genes, across extensive portions of the human genome.

Base Sequence↗
PubMed1991

Refinement of human chromosome 7 map around the pro alpha 2(I)collagen gene by long-range restriction mapping.

The physical proximity of the closely linked pro alpha 2(1)collagen (COL1A2) and erythropoietin (EPO) genes and five loci with no known function was studied by long-range restriction mapping experiments using pulsed-field gel electrophoresis. COL1A2 and D7S64 were found to be within 100 kb of each other, providing a new informative marker for linkage studies with respect to COL1A2. D7S15 and D7S79 were within 350 kb of each other. The physical distance between COL1A2 and EPO was determined to be at least 600 kb. Two CpG rich islands were recognized within 600 kb of COL1A2, suggesting that other genes might lie in the vicinity of COL1A2.

Chromosomes, Human, Pair 7↗
PubMed1991

DNA discontinuities in the domain of amplified human MYC oncogenes.

COLO320DM and COLO320HSR are cell lines derived from a human colon carcinoma. Both lines have an amplification of the MYC oncogene: COLO320DM in the form of double minute chromosomes, COLO320HSR as a large marker chromosome with homogeneously staining regions. We have used pulsed field gel electrophoresis (PFGE) to analyze undigested DNA from both COLO320 cell lines. Upon blotting and hybridization with a MYC probe, the autoradiograms showed the existence of discontinuities in the amplified DNA domains. Additional evidence indicating a preferential concentration of DNA breaks in the region containing the MYC amplicons was obtained with the alkaline unwinding technique. We propose that amplicons are connected by hairpin formation or Hoogsteen pairing between free DNA ends.

Adenocarcinoma↗
PubMed1991

Yeast artificial chromosome-based genome mapping: some lessons from Xq24-q28.

Yeast artificial chromosomes (YACs) have recently provided a potential route to long-range coverage of complex genomes in contiguous cloned DNA. In a pilot project for 50 Mb (1.5% of the human genome), a variety of techniques have been applied to assemble Xq24-q28 YAC contigs up to 8 Mb in length and assess their quality. The results indicate the relative strength of several approaches and support the adequacy of YAC-based methods for mapping the human genome.

Chromosome Mapping↗
PubMed1991

Intrachromosomal rearrangements fusing L-myc and rlf in small-cell lung cancer.

Chromosomal abnormalities affecting proto-oncogenes are frequently detected in human cancer. Oncogenes of the myc family are activated in several types of tumors as a result of gene amplification or chromosomal translocation. We have recently found the L-myc gene involved in a gene fusion in small-cell lung cancer (SCLC). This results in a chimeric protein with amino-terminal sequences from a novel gene named rif joined to L-myc. Here we present a preliminary structural characterization of the rlf-L-myc fusion gene, which has been found only in cells with an amplified L-myc gene. In addition, we have used somatic cell hybrids to assign the normal rlf locus to the same chromosome (chromosome 1) on which L-myc resides. Finally, we have been able to establish a physical linkage between rif and L-myc with pulsed-field gel electrophoresis. Our results demonstrate that normal rlf and L-myc genes are separated by less than 800 kb of DNA. Thus, the rlf-L-myc gene fusions are due to similar but not identical intrachromosomal rearrangements at 1p32. The presence of independent genetic lesions that cause the formation of identical chimeric rlf-L-myc proteins suggests a role for the fusion protein in the development of these tumors.

Animals↗
PubMed1990

Finnish hereditary amyloidosis is caused by a single nucleotide substitution in the gelsolin gene.

The amyloid protein in Finnish hereditary amyloidosis is a fragment of the actin-filament binding region of a variant gelsolin molecule. Here we demonstrate, using polymerase chain reaction and allele-specific oligonucleotide hybridization analyses of genomic DNA, a single base mutation (G654----A654) in the gelsolin gene segment encoding the amyloid protein. The mutation is responsible for the expression of the variant (Asn187) gelsolin molecule in Finnish hereditary amyloidosis. The nucleotide substitution was found in all five unrelated patients with Finnish amyloidosis studied, but not in 45 unrelated control subjects. The mutation co-segregated with the disease phenotype in a family with Finnish amyloidosis. The results show that a single substitution in the gelsolin gene causes Finnish hereditary amyloidosis. The allele-specific oligonucleotide hybridization method provides a simple and accurate means of detecting this mutation.

Amyloidosis↗
PubMed1990

Cystic fibrosis mutation delta F508 in Finland: other mutations predominate.

The frequency of mutation delta F508 was determined in all 20 Finnish cystic fibrosis (CF) families with living affected children (19 with pancreatic insufficiency). delta F508 was detected in 18 out of 40 CF chromosomes (45%). At least two different mutations associated with pancreatic insufficiently have occurred in a rare haplotype defined by XV2c, CS.7, KM19 alleles 1 2 2. Geographical clustering of delta F508 and other mutations suggested that a founder effect and genetic drift have influenced the frequency of mutations causing CF in Finland.

Child↗
PubMed1990

Craniofrontonasal dysostosis: variable expression in a three-generation family.

A family with craniofrontonasal dysostosis (craniofrontonasal dysplasia) is described. There were three severely affected females, two of them daughters of apparently healthy parents. Examination of the male relatives revealed orbital hypertelorism and other minor anomalies in two of them, including the father of the two affected daughters. This family emphasizes the wide variation in the phenotype of craniofrontonasal dysostosis and suggests that male relatives with minor manifestations of the syndrome may be at high risk of having severely affected daughters. The expression of the gene may be modified by the sex.

Adult↗