Nobuaki Kikyo, M.D., Ph.D.

Dr. Kikyo is an Assistant Professor of Medicine and a member of the Stem Cell Institute and the Cancer Center.  He received his M.D. in 1987 and Ph.D. in 1993 from Tokyo University Medical School, Japan.  He studied genomic imprinting in Dr. Azim Surani’s laboratory at Wellcome/CRC Institute, University of Cambridge as a postdoctoral fellow. He then moved to Dr. Alan Wolffe’s laboratory at NIH to start biochemical analysis of somatic cell nuclear cloning in Xenopus.  He joined the University of Minnesota in 2000.

Dr. Kikyo’s main interest is molecular analysis of nuclear remodeling in somatic cell nuclear cloning. Nuclear cloning is a procedure to create genetically identical animals by injecting somatic nuclei into unfertilized eggs.  Recent success in mammalian cloning with differentiated adult nuclei strongly indicates that egg cytoplasm contains unidentified remarkable reprogramming activities with the capability to erase previous memory of cell differentiation. At the heart of this nuclear reprogramming lies chromatin remodeling since chromatin structure and function define cell differentiation through regulation of the transcriptional activities of the cells.  However, despite the long history and current intensive research on nuclear cloning, little is known about the molecular mechanisms responsible for the chromatin remodeling associated with nuclear cloning.  The long-term goal of Dr. Kikyo’s group is to understand how differentiated somatic nuclei are dedifferentiated in egg cytoplasm and are redifferentiated during the subsequent embryogenesis. Once the mechanisms are understood, they can be applied to creation of new tissues using patients’ somatic cells for transplantation medicine without using ethically controversial embryonic materials. 

Guschin D, Wade PA, Kikyo N, Wolffe AP. (2000) ATP-dependent histone octamer mobilization and histone deacetylation mediated by the Mi-2 chromatin remodeling complex.  Biochemistry 39, 5238-5245

Kikyo N, Wade PA, Guschin D, Ge H, Wolffe AP. (2000) Active remodeling of somatic nuclei in egg cytoplasm by the nucleosomal ATPase ISWI. Science 289, 2360-2362

Guschin D, Geiman TM, Kikyo N, Tremethick DJ, Wolffe AP, Wade PA. (2000) Multiple ISWI ATPase complexes from Xenopus laevis: functional conservation of ACF but not of CHRAC or NURF. J Biol Chem 275, 35248-55

Wade PA, Kikyo N. (2002) Chromatin remodeling in nuclear cloning. Eur J Biochem  269, 2284-2287

Gonda K, Fowler J, Katoku-Kikyo N, Haroldson J, Wudel J, Kikyo N. (2003)  Reversible disassembly of somatic nucleoli by the germ cell proteins FRGY2a and FRGY2b. Nature Cell Biol 5, 205-10          

Tamada H, Kikyo N. (2004) Nuclear reprogramming in mammalian somatic cell nuclear cloning.  Cytogenetics Genome Res, 105, 285-291