혈청반응인자(SRF)가 FAST-1 의존적인 Activin 신호전달에 미치는 영향 연구

학위논문(박사) - 한국과학기술원 : 생명과학과, 2007.2, [ x, 92 p. ]Activin is a member of TGF-beta superfamily of growth and differentiation factors and has been shown to play a role in regulation of reproductive endocrine system, erythroid differentiation and mesoderm-induction of an embryo. Serum response factor (SRF) is a MADS box-containing transcription factor mediating the rapid transcriptional response to extracellular stimuli such as growth, stress, or differentiation signals. In this study, it was found that SRF inhibited Activin/FAST-1-dependent transcription using ARE-Luc reporter. SRF associated with both Smad2 and FAST-1 mediating Activin/FAST-1-dependent transcription. Furthermore, MH2 domain of Smad2 was required for interaction of Smad2 with SRF. MADS box domain of SRF interacted with FAST-1 and suppressed Activin/FAST-1-dependent transcription. It was also found that SRF associated with forkhead DNA-binding domain of FAST-1. SRF did not suppress either phosphorylation of Smad2 or Smad2-Smad4 complex formation induced by Activin. However, SRF reduced Activin-induced formation of Smad2-FAST-1 complex. Because Activin/FAST-1-dependent transcription is essential for the mesoderm induction and axial patterning in Xenopus embryos, functions of Xenopus SRF (XSRF) in Xenopus early embryos were also examined. Ectopic expression of XSRF RNA inhibited mesoderm induction, both in marginal zone in vivo and by Activin signal in animal caps, and it also caused the embryonic malformations shown at later stages including anterior truncation and shortened body axis. These phenotypic defects were rescued by coexpression of a constitutively active form of FAST-1. Conversely, morpholino-mediated depletion of XSRF expanded the expression of mesodermal genes toward the ectodermal territory, and caused not only the severely shortened body axis and truncation of anterior structures but also defective gastrulation movement in Xenopus embryos. These axial defects by XSRF morpholino were rescued by coexpression of a constitutively repre...한국과학기술원 : 생명과학과

Pinus maritima Extract (Pycnogenol)와 Ulmus macrocarpa Extract에 의한 항산화 효과

학위논문(석사) - 한국과학기술원 : 생물과학과, 2000.2, [ viii, 49 p. ]In this study, we investigated the antioxidant activity of Pycnogenol^® and Ulmus macrocarpa extract. Pycnogenol^® is proprietary extract of the bark of the French maritime pine tree (Pinus maritime). The Extracts from the bark of pine have been used in the past in different parts of the world in traditional medicine and are believed to affect various pathologies raging from vascular disease to arthritis. Ulmus macrocarpa is a deciduous tree which is distributed in Asia-temperate regions and the stem and root bark have been used in oriental traditional medicine for treatment of oedema, mastitis, gastric cancer and inflammation. Both Pycnogenol and Ulmus macrocarpa extract inhibited the deoxyribose degradation by hydroxyl radical and also inhibited NBT reduction by superoxide anion in vitro. But both didn``t scavenge hydrogen peroxide. Both Pycnogenol^® and Ulmus macrocarpa extract protected the single-strand breaks in the plasmid DNA by Fe(II) and H2O2, and also by xanthine oxidase /hypoxanthine. But Pycnogenol^® protected only up to 25㎍/ml whereas over 25㎍/ml of this showed the prooxidant activity. Pycnogenol^® and Ulmus macrocarpa extract inhibited Fe(II) autooxidation and increased the Fe(III) reduction. Pycnogenol^® showed more stronger prooxidant activity converting Fe(III) to Fe(II) than Ulmus macrocarpa extract. We also observed Pycnogenol^® and Ulmus macrocarpa extract could protect the isolated plasmid DNA through chelating Fe(II) ions.한국과학기술원 : 생물과학과