KOREASCHOLAR

For many years, experience has been accumulated on embryo and gamete manipulation in mammals, The present work is an introduction of these techniques and their possible application in human embryology in s pecific cases, Mammalian c1on ing has been studied by many groups, but the success rate is sti ll low‘ Removal of maternal chromosomes from unfertil ized oocytes and injection of donor cells into enucleated oocytes are the most important factors for the improvement of cloning effi cien cy, Here, we introduce a novel one-step rnicromanipulation (OSM) system and laser-assisted zona pellucida piel'cing technique (LAZP) , 1n genera l, somatic cell nuclear transfer (SCNT) is completed by many processes including enucleation and donor cell fusion , Howevel', OSM is a simple method because donor cell is directly injected into ooplasm without fusion pl'ocess, 1n addition, chromosomal enucleation and donor cell inj ec tion are perfOl‘med simultaneously in OSM, While OSM was a pplied to porcine SCNT, LAZP was a pplied to murine SCNT, This rninirni zed the use of piezo-dri ven micromanipul ator (P1EZO) , I'educing chances 0 1' problems caused by P1EZO pulses, LAZP reduced time that took to pierce zona pellucida in removal of nucleus fl'om oocyte and somatic cell injection, which might have taken longer time with P1EZO, The simple , new OSM and LAZP system may help to enable large scale cloning by reduction of procedural steps, Pa l'thenogenesis de scribes the growth and development of an embryo without fertilization by a male Parthenogenetic ES cell s (PESCs) can be a useful cell source for tissue I'epail‘ and I'egeneration , Moreover , the defects in full-term developrnent of this PESCs enable researc hers to avoid the ethical concern , Here, the author showed that PESCs can differentiate into osteogenic lineage, The PESCs were induced osteogenic dlfferentlatlon The osteoblas t-specific gene expression such as osteocalcine, osteopontine, osteonectin, bone-sialo protein‘ coll agen type-l and alka line phos phatase showed osteogenic potential of differentiated PESCs, The author also focused on the neuronal induction of murine PESCs by simplified neurona l induction system to generate doparninergic (DA) neurons , As a result , PESCs were differentiated into nestin and Tuj-l positive cell s successfully, a lthough t he generation of DA neuron was Illruted For murine embryo cul ture, novel oil-free microtube cul tu re system was applied , This new culture system provides oil-free cu ltu re condi t ions and is easy to handle It was also associated with faster development and mOl'e t l'ophectodel'mal cells , which will enhance the development of murine embl'Yos to fur t hel' stages ,

• Sangho Roh(Craniomaxillofacial Reconstructive Sciences Major, Dental Research Institute, and CLS21, Seoul National University School of Dentistry)