Mutations of the NF1 gene in Korean Neurofibromatosis type 1 patients

BACKGROUND: Neurofibromatosis type 1 (NF1) is one of the most common inherited disorders and is characterized by abnormalities in multiple tissues derived from the neural crest. OBJECTIVES: We analyzed the presence of mutations of NF1 gene in unrelated 56 Korean NF-1 patients. METHODS: Mutations were detected by polymerase chain reaction, single strand conformational polymorphism analysis and direct DNA sequencing. RESULTS: We found five different kinds of mutations in the NF1 gene from 5 out of 56 unrelated Korean NF1 patients. Sequence analysis revealed a nucleotide substitution at codon 1276 of exon 22 (CGA to TGA, R1276X), 4 by insertion at codon 1270 of exon 22 (3809 ins TGGA), a base pair deletion at codon 1398 of exon 24 (4192 del G), 4 by deletion at codon 1638 of exon 28 (4914 del CTCT), and a base pair substitution at codon 1947 of exon 31 (CGA to TGA, R1947X). All of these mutations resulted in premature termination of the mutant alleles. CONCLUSION: Results showed that common consequences of NF1 mutations are introduction of a premature stop codon, and these mutant genes may encode truncated forms of neurofibromin.

Caspases Activation in Ultraviolet B-induced Apoptosis of G361 Human Melanoma Cell Line

BACKGROUND: Ultraviolet B (UVB) irradiation can induce apoptosis of melanocytes and melanoma cells. However, mechanism of UVB-induced apoptosis of melanoma cells is not clarified yet. OBJECTIVE: Our purpose was to study the molecular mechanism of UVB-induced apoptosis of melanoma cells. METHODS: G361 lightly pigmented melanoma cells were analyzed for apoptotic mechanism by flow cytometry and western blotting. RESULTS: G361 melanoma cells showed apoptotic features with gradual increment of UVB doses by MTT and flow cytometry. Western blotting disclosed activation of caspase-3 and poly (ADP-ribose) polymerase (PARP) after UVB irradiation. CONCLUSION: In this study, we showed that UVB-induced apoptosis of melanoma cells is mediated by PARP activation which is induced by caspase cascade.

Attachment and Growth of Cultured Fibroblasts on Chitosan Sponge

Closure of large skin wounds with split-thickness skin graft requires extensive harvesting of autologous skin. The limitation of available donor areas has sought various kinds of skin equivalents for coverage of skin defects. Concept of living skin equivalent using fibroblast and keratinocyte is the most promising one. For seeking ideal artificial skin, we conducted a research of new dermal alternative using chitosan. Fibroblast scattered on chitosan and chitosan-collagen sponge polymers were cultured for 3 weeks and chitosan and chitosan-collagen sponge polymers were grafted on the back of 250 gm Sprague-Dawley rat. There was statistically significant difference in fibroblast attachment as well as fibroblast proliferation between chitosan and chitosan-collagen sponge. Four weeks after grafting, the grafted area was examined. In the area of chitosan sponge graft, there was no clinical sign of inflammation. However, mild inflammatory infiltration and a few multinucleated giant cells were observed. In contrast, chitosan-collagen sponge grafted area showed no foreign body reaction clinically and histologically. In conclusion, concomitant use of chitosan and collagen resulted in better fibroblast attachment and proliferation and minimal immunologic reaction than chitosan sponge.

Identification of two novel frame shift mutations of the NF1 gene in Korean patients with neurofibromatosis type 1

Neurofibromatos is type 1 (NF1) is one of the most common inherited disorders and is characterized by abnormalities in multiple tissues derived from the neural crest. The NF-1 gene has been cloned and mapped to human chromosome 17q11.2. The NF-1 gene has an open reading frame that predicts a protein consisting of 2,818 amino acids, known as neurofibromin. Here, we report two kinds of novel frame shift mutations of the NF1 gene from 2 out of 56 unrelated Korean NF1 patients. These mutations were detected using polymerase chain reaction and single strand conformational polymorphism analysis. Sequencing analysis revealed four base pair insertion at codon 1270 of exon 22, and a base pair deletion at codon 1398 of exon 24. These mutations resulted in premature termination of the mutant alleles and may encode truncated forms of neurofibromin.