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Biomedical subjects

M Dean

Publications and source records attributed to M Dean.

At least 181 records · Page 10Linked to original sources
PubMed1996

Mapping of 22 Notl linking clones on human chromosome 3 by polymerase chain reaction and somatic cell hybrid panels.

Twenty-two human chromosome 3 derived and partially sequenced Notl linking clones were mapped using two somatic cell hybrid panels. Somatic cell hybrid mapping was performed by Southern hybridization and/or by polymerase chain reaction (PCR), using 300-500 bp CpG-rich sequences surrounding Notl sites. Thus, 22 new Notl site-tagged (sequence tagged sites) STSs were created, distributed over the entire human chromosome 3. The majority of these linking clones tag known or unknown expressed sequences (genes). Together with other physical and genetic mapping methods, localization of Notl linking clones facilitates the construction of a long-range physical map and, at the same time, a transcriptional map of human chromosome 3.

Animals↗
PubMed1996

Cystic fibrosis gene mutations detected in hereditary pancreatitis.

To determine the potential role of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene in the etiology of Hereditary Pancreatits (HP), we analyzed this gene in two HP families. PCR-SSCP analysis was employed, followed by direct sequencing of DNA samples showing alterations by SSCP. A new alteration not yet detected in connection with CF was detected in one HP family. The alteration is in exon 7 and causes an amino acid change from Leu to Arg at position 327 (L327R). L327R segregates with the disease within the family. We discovered another novel alteration (V1190P) in an HP patient of the second family. These results indicate that CFTR gene mutations may be involved in the etiology of HP and represent a challenge for further study of the role of (CTFR) in other digestive diseases.

Autoradiography↗
PubMed1996

The role of the human homologue of Drosophila patched in sporadic basal cell carcinomas.

Basal cell carcinoma (BCC) is the most common cancer in humans. The majority of sporadic BCCs have allele loss on chromosome 9q22 implying that inactivation of a tumour suppressor in this region is an important step in BCC formation. The gene for nevoid basal cell carcinoma syndrome (NBCCS), an autosomal dominant disorder characterized by multiple BCCs, maps to the same region and is presumed to be the tumour suppressor inactivated at this site. NBCCS has been identified recently and encodes a protein with strong homology to the Drosophila segment polarity gene, patched. Analysis of Drosophila mutants indicates that patched interacts with the hedgehog signalling pathway, repressing the expression of various hedgehog target genes including wingless, decapentaplegic and patched itself. Using single strand conformational polymorphism (SSCP) to screen human patched in 37 sporadic BCCs, we detected mutations in one-third of the tumours. Direct sequencing of two BCCs without SSCP variants revealed mutations in those tumours as well suggesting that inactivation of patched is probably a necessary step in BCC development. Northern blots and RNA in situ hybridization showed that patched is expressed at high levels in tumour cells but not normal skin suggesting that mutational inactivation of the gene leads to overexpression of mutant transcript owing to failure of a negative feedback mechanism.

Animals↗
PubMed1996

Characterization of the human ABC superfamily: isolation and mapping of 21 new genes using the expressed sequence tags database.

As an approach to characterizing all human ATP-binding cassette (ABC) superfamily genes, a search of the human expressed sequence tag (EST) database was performed using sequences from known ABC genes. A total of 105 clones, containing sequences of potential ABC genes, were identified, representing 21 distinct genes. This brings the total number of characterized human ABC genes from 12 to 33. The new ABC genes were mapped by PCR on somatic cell and radiation hybrid panels and yeast artificial chromosomes (YACs). The genes are located on human chromosomes 1, 2, 3, 4, 6, 7, 10, 12, 13, 14, 16, 17 and X; at locations distinct from previously mapped members of the superfamily. The characterized genes display extensive diversity in sequence and expression pattern and this information was utilized to determine potential structural, functional and evolutionary relationships to previously characterized members of the ABC superfamily.

ATP-Binding Cassette Transporters↗
PubMed1996

Molecular analysis of chromosome 9q deletions in two Gorlin syndrome patients.

Gorlin syndrome is an autosomal dominant disorder characterized by multiple basal cell carcinomas, medulloblastomas, ovarian fibromas, and a variety of developmental defects. All affected individuals share certain key features, but there is significant phenotypic variability within and among kindreds with respect to malformations. The gene (NBCCS) maps to chromosome 9q22, and allelic loss at this location is common in tumors from Gorlin syndrome patients. Two recessive cancer-predisposition syndromes, xeroderma pigmentosum group A (XPAC) and Fanconi anemia group C (FACC), map to the NBCCS region; and unusual, dominant mutations in these genes have been proposed as the cause of Gorlin syndrome. This study presents cytogenetic and molecular characterization of germ-line deletions in one patient with a chromosome 9q22 deletion and in a second patient with a deletion of 9q22-q3l. Both have typical features of Gorlin syndrome plus additional findings, including mental retardation, conductive hearing loss, and failure to thrive. That Gorlin syndrome can be caused by null mutations (deletions) rather than by activating mutations has several implications. First, in conjunction with previous analyses of allelic loss in tumors, this study provides evidence that associated neoplasms arise with homozygous inactivation of the gene. In addition, dominant mutations of the XPAC and FACC1 genes can be ruled out as the cause of Gorlin syndrome, since the two patients described have null mutations. Finally, phenotypic features that show variable expression must be influenced by genetic background, epigenetic effects, somatic mutations, or environmental factors, since these two patients with identical alterations (deletions) of the Gorlin syndrome gene have somewhat different manifestations of Gorlin syndrome.

Adolescent↗