Home  About us  Contact
 

DNA Sequencing Analysis (dna + sequencing_analysis)

Distribution by Scientific Domains
Life Sciences60%
Medical Sciences40%

Selected Abstracts

Compound heterozygosity in sibling patients with recessive dystrophic epidermolysis bullosa associated with a mild phenotype

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 3 2006
Y. Shibusawa MD
We describe two cases of a 3-year-old Japanese boy and his 1-year-old sister presenting recessive dystrophic epidermolysis bullosa; a relatively mild phenotype. Blistering and scarring were limited to the acral region, and some fingernails and toenails were lost. PCR-RFLP and DNA sequencing analyses revealed compound heterozygotes for a splice-site mutation (6573 +1GtoC) and a nonsense mutation (E2857X) in the type VII collagen gene (COL7A1). Both mutations caused a premature termination codon (PTC). The mutation E2857X was located behind the candidate cleavage site within the NC-2 domain required for the assembly of anchoring fibrils. This PTC position may explain their mild phenotype. [source]

Scale-up development of high-performance polymer matrix for DNA sequencing analysis

ELECTROPHORESIS, Issue 19 2006
Fen Wan
Abstract Linear polyacrylamide (LPA) has been widely used as a replaceable separation matrix in CE. An increase in the molecular weight of the separation medium favors the separation of larger DNA fragments. In order to obtain ultrahigh-molecular-weight (UHMW) LPA, a "frozen" method was developed to synthesize the LPA homopolymer. This approach has three major advantages when compared with other existing routes of LPA synthesis: (i),long LPA chains could be obtained easily, with their average molecular weight (MW) being in the high 10,MDa range; (ii),the desired MW could be adjusted over a broad range by controlling the temperature and the concentration of initiators during synthesis; (iii),the product solution contains only a tiny amount of impurity besides the solvent and LPA. Both static and dynamic laser light scattering measurements were carried out to characterize the synthesized LPA in the buffer solution. The DNA sequencing matrix prepared from LPA using this method was studied and the results were compared with the newly developed commercial product POP7 from Applied Biosystems. It should be noted that this approach can be applied to synthesize other water-soluble polymers, resulting in UHMW products because the chain transfer constant is smaller at lower temperatures. [source]

Novel MLH1 mutations and a novel MSH2 polymorphism identified by SSCP and DHPLC in Portuguese HNPCC families,,

HUMAN MUTATION, Issue 5 2003
G. Isidro
Abstract Mismatch repair genes MSH2 and MLH1 are the two major genes implicated in hereditary nonpolyposis colorectal cancer. For the past years, we have successfully searched for mutations in both genes in affected Portuguese families, by SSCP and DNA sequencing analysis but because of the advantages that DHPLC offers, we have established conditions in our laboratory to use this new method. While screening for mutations by both methods, in 35 individuals belonging to HNPCC Portuguese families, 4 novel MLH1 mutations (c.307-1G>C; c.1023delG [p.R341fsX366]; c.2154_2155delCA [p.H718fsX721], c.2154_2155dupCA [p.I719fsX782]), an unclassified variant (c.-28A>T) and one silent MSH2 polymorphism (c.2766T>C) have been identified. © 2003 Wiley-Liss, Inc. [source]

DNA demethylation of vascular endothelial growth factor-C is associated with gene expression and its possible involvement of lymphangiogenesis in gastric cancer

INTERNATIONAL JOURNAL OF CANCER, Issue 8 2007
Shunji Matsumura
Abstract Previous studies have indicated that lymphangiogenesis in solid tumors is associated with lymphatic metastasis. Overexpression of Vascular endothelial growth factor (VEGF)-C plays a major role in lymphangiogenesis in cancers. In the present study, DNA methylation and expression of the VEGF-C gene was investigated in gastric cancer (GC). Four GC cell lines (MKN-45, MKN-74, HSC-39 and HSC-43) showed no expression of VEGF-C, and the VEGF-C gene was found to be methylated in these cells. In contrast, 7 GC cell lines (MKN-1, MKN-7, MKN-28, TMK-1, KATO-III, SH101-P4 and HSC-44PE) expressed VEGF-C, and the VEGF-C gene was found to be unmethylated in these cell lines. In addition, expression of VEGF-C mRNA was retrieved by treatment with a demethylating agent, Aza-2,-deoxycytidine. In GC tissue samples, bisulfite DNA sequencing analysis revealed that VEGF-C was not methylated in 9 (29.0%) of 31 GC samples, whereas demethylation was not observed in corresponding non-neoplastic mucosa samples. Overexpression of VEGF-C mRNA was observed in 16 (51.6%) of 31 GC samples by quantitative reverse transcription-polymerase chain reaction. Of the 9 GC cases with VEGF-C demethylation, 8 (88.9%) overexpressed VEGF-C. In contrast, of the 22 GC cases without VEGF-C demethylation, 8 (36.4%) overexpressed VEGF-C (p = 0.0155). Furthermore, lymphatic vessel density determined by immunostaining of podoplanin in GC tissues was associated with overexpression of VEGF-C (p < 0.0001). These results suggest that demethylation and activation of the VEGF-C gene is likely involved in lymphangiogenesis in GC. © 2007 Wiley-Liss, Inc. [source]

Molecular and phenotypic characteristics of patients with phenylketonuria in Serbia and Montenegro

CLINICAL GENETICS, Issue 2 2006
M Stojiljkovic
Phenylketonuria (PKU) is the most common inborn error of amino acid metabolism in Caucasians. PKU is caused by mutations in the gene encoding phenylalanine hydroxylase (PAH) enzyme. Here, we report the spectrum and the frequency of mutations in the PAH gene and discuss genotype,phenotype correlation in 34 unrelated patients with PKU from Serbia and Montenegro. Using both polymerase chain reaction,restriction fragment length polymorphism and ,broad-range' denaturing-gradient gel electrophoresis/DNA sequencing analysis, 19 disease-causing mutations were identified, corresponding to mutation detection rate of 97%. The most frequent ones were L48S (21%), R408W (18%), P281L (9%), E390G (7%) and R261Q (6%), accounting for 60% of all mutant alleles. The genotype,phenotype correlation was studied in homozygous and functionally hemizygous patients. We found that the most frequent mutation, L48S, was exclusively associated with the classical (severe) PKU phenotype. The mutation E390G gave rise to mild PKU. For the mutation R261Q, patients had been recorded in two phenotype categories. Considering allele frequencies, PKU in Serbia and Montenegro is heterogeneous, reflecting numerous migrations over the Balkan Peninsula. [source]