rpoB gene sequencing for phylogenetic analysis of avian pathogenic Escherichia coli / 대한수의학회지

The present study was conducted to determine the full rpoB and eight house-keeping gene sequences of 78 and 35, respectively, avian pathogenic E. coli (APEC) strains. Phylogenetic comparison with 66 E. coli and Shigella strains from GenBank and EMBL was also conducted. Based on the full rpoB sequence, 50 different rpoB sequence types (RSTs) were identified. RST 1 was assigned to a major RST that included 34.7% (50/144) of the analyzed strains. RST 2 to RST 50 were then assigned to other strains with higher nucleotide sequence similarity to RST 1 in order. RST 1, 11, and 23 were mixed with APEC along with human commensal and pathogenic strains while RST 2, 6, 9, 13-15, 22, 24, 25, 33, 34, 36, and 41 were unique to APEC strains. Only five APEC strains grouped into RST 32 and 47, which contained human pathogenic E. coli (HPEC). Thus, most of the APEC strains had genetic backgrounds different from HPEC strains. However, the minor APEC strains similar to HPEC should be considered potential zoonotic risks. The resolution power of multi-locus sequence typing (MLST) was better than RST testing. Nevertheless, phylogenetic analysis of rpoB was simpler and more economic than MLST.

Germline Mutations of the NF2 Gene in Korean Neurofibromatosis 2 Patient / 대한암학회지

PURPOSE: Neurofibromatosis 2(NF2) is an autosomal dominant disease characterized by development of bilateral acoustic neuroma and various central nervous system tumors such as meningiomas, ependymomas, and schwannomas. Recent cloning of the gene responsible for NF2, the NF2 gene, permits the presymptomatic genetic diagnosis of affected individuals by direct analysis of the gene. This paper was intended to identify germline mutations in Korean NF2 patients. MATERIALS AND METHODS: We collected blood samples from 15 clinically diagnosed NF2 patients treated at the Department of Neurosurgery, Seoul National University Hospital. Purified genomic DNA samples were analyzed for mutations of the NF2 gene by using polymerase chain reaction(PCR)-single strand conformation polymorphism(SSCP) method followed by direct DNA sequencing. RESULTS: We were able to identify germline mutation of the NF2 gene in one patient. The mutation identified was 1 base pair deletion(A) at codon 318, resulting in premature stop codon due to frameshift. CONCLUSION: Identification of the germline mutation in NF2 gene should enable us to test all individual family members at risk to determine whether or not they carry the mutant NF2 gene.

Germline Mutation of BRCA2 Gene in Korean Breast / Ovarian Cancer Families / 대한암학회지

PURPOSE: Recent discovery of BRCA1 and BRCA2 genes has made it possible to perform presymptomatic diagnosis in hereditary breast/ovarian cancer families. We have previously reported germline mutations of the BRCA1 gene in Korean hereditary breast/ovarian cancer families. In that study two out of 13 families were found to have germline mutations in BRCA1 gene. One was a nonsense mutation in codon 1815, and the other was a frameshift mutation due to 2 base-pair deletion in codon 1701 of BRCA1 gene. This study was intended to identify germline mutations of the BRCA2 gene in Korean breast/ovarian cancer families. MATERIALS AND METHODS: Peripheral blood DNA was obtained from 10 breast cancer patients registered at the Korean Hereditary Tumor Registry with positive family history of breast and/or ovarian cancer. Exons 11 and 27 of the BRCA2 gene(together accounting for 50% of the coding region of the BRCA2 gene) were amplified by polymerase chain reaction(PCR) and screened for mutations by in vitro transcription/translation method. For confirmation of the mutations, automatic sequencing of the PCR products displaying abnormal truncated protein bands was perfomed. RESULT: We identified an abnormal truncated protein in the exon 11 of the BRCA2 gene from a member of hereditary breast cancer family, SNU-B4. Sequencing analysis revealed a 4 bp deletion in codons 1248-49 of the exon 11, resulting in frameshift that led to premature stop codon and truncation of the protein product. CONCLUSION: We have identified a germline mutation from a Korean hereditary breast cancer family. So far only one case of the same mutation has been registered in Database of BRCA2 mutation (BIC) by a commercial genetic diagnosis company, Myriad Genetics, Inc. Identification of the germline mutation in BRCA2 gene should aid in the accurate presymptomatic diagnosis of the at-risk members in this family.

Germline Mutations of BRCA1 Gene in Korean Breast and/or Ovarian Cancer Families / 대한암학회지

PURPOSE: To understand the involvement of BRCA1 gene in Korean breast and/or ovarian cancer families. MATERIALS AND METHODS: Germline mutations of BRCA1 gene were analyzed in 13 families which included 3 hereditary site-specific breast cancer families, 6 suspected breast cancer families, and 3 suspected breast-ovarian cancer family, and one Li-Fraumeni family by screening BRCA1 gene using single strand conformation polymorphism (SSCP) analysis on polymerase chain reaction (PCR) amplified genomic DNA and confirmed the results by sequencing. RESULTS: Including one family with previously reported nonsense mutation of BRCA1 gene, we detected two mutations in unrelated families. One newly identified mutation was frame shift mutation resulting from TG deletion in codon 1701, which results in a truncated BRCA1 protein, at codon 1714. CONCLUSION: The proportion of families who inherit the mutated BRCA1 gene seems to be small among Korean breast and/or ovarian cancer families.