부산대학교 도서관

SCOPE:: Impaired folate metabolism increases the risk of birth defects, neurodegenerative and cardiovascular disease, osteoporosis and cancer. We used Caenorhabditis elegans to investigate impaired folate metabolism by RNA interference of key enzymes in the methionine synthase (MS) and thymidylate synthase (TS) cycle and by folate deficiency and over-supplementation feeding studies. METHODS AND RESULTS:: Folate status is influenced by genetic variations (polymorphisms), folate deficiency and supplementation. Single RNAi of dihydrofolate reductase (DHFR), methylenetetrahydrofolate reductase (MTHFR) and MS revealed that gene regulation is largely affected in both folate cycles. Adaptation requires a close transcriptional connection between TS and MS cycle. Coupled DHFR and MS expression is required to balance both cycles, but seems to reduce the overall rate of folate conversion. Feeding studies showed that folate over-supplementation to functioning metabolism inactivates MS and MTHFR expression and enhances TS activity, which favors DNA synthesis over methylation reactions. Folate deficiency disrupted homeostasis by favoring TS cycle and led to malformation in C. elegans offspring. Embryos show aneuploidy and are nonviable lacking DNA repair during meiotic stage of diakinesis. CONCLUSION:: Single gene silencing alters gene expression in both cycles and disrupts folate homeostasis. Folate over-supplementation and deficiency favors TS over MS cycle and causes prophase DNA damage. : Human folate metabolism is influenced by genetic variations (polymorphisms), folate deficiency and supplementation. We used Caenorhabditis elegans to investigate impaired folate metabolism by RNA interference of key enzymes in the methionine synthase (MS) and thymidylate synthase (TS) cycle. Single gene silencing alters gene expression in both cycles and disrupts homeostasis. Feeding studies on folate supplementation and deficiency show that both conditions favor TS over MS cycle. Folate deficiency causes malformation in C. elegans offspring lacking prophase DNA repair.(Figure is included in full-text article.)