Biomedical Research Education & Training
Faculty Member

Ohi, Ryoma, Ph.D.
Associate Professor of Cell and Developmental Biology

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Phone Number: 615-936-7782

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Ohi, Ryoma's picture
Academic history
Ph.D., Vanderbilt
B.S., Vanderbilt
Research Fellow, Harvard Medical School

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4150A MRB III 37232-8240

Research Keywords
Mitosis, Microtubules, Microtubule Motors,Biochemistry,Cancer,Cell cycle,Chromosome,Enzyme action,Phosphorylation

Research Specialty
Microtubule organization and dynamics during cell division

Research Description
Our group studies animal cell division. During this process, the microtubule cytoskeleton is organized into a transient structure called the mitotic spindle. This apparatus attaches replicated chromosomes via kinetochores and generates forces that power the division of chromosomes among two daughter cells. We apply a multidisciplinary approach to examine the process of mitotic spindle assembly and the interface between kinetochores and microtubules. We use quantitative light microscopy to investigate protein behavior in the mitotic spindle, biochemistry to understand the function of key mitotic regulators, and small molecules to perturb spindle function. Our long term goal is to use our findings to develop new anti-mitotic oncological therapies. Currently, our lab is studying how several families of kinesin-like proteins impact spindle assembly and function in animal cells. We are particularly interested in the roles of the kinesin-8s at spindle microtubule plus-ends, the mechanisms by which the kinesin-5 and kinesin-12 motors enforce spindle bipolarity, and the roles of kinesin-13s during cytokinesis.

Gayek, AS, Ohi, R. Kinetochore-microtubule stability governs the metaphase requirement for Eg5. Mol Biol Cell, 2014

Sturgill, EG, Ohi, R. Microtubule-regulating kinesins. Curr Biol, 23(21), R946-8, 2013

Sturgill, EG, Ohi, R. Kinesin-12 Differentially Affects Spindle Assembly Depending on Its Microtubule Substrate. Curr Biol, 2013

Archuleta, TL, Du, Y, English, CA, Lory, S, Lesser, C, Ohi, MD, Ohi, R, Spiller, BW. The Chlamydia effector, chlamydial outer protein N CopN), sequesters tubulin and prevents microtubule assembly. J Biol Chem, 2011

Chen, JS, Lu, LX, Ohi, MD, Creamer, KM, English, C, Partridge, JF, Ohi, R, Gould, KL. Cdk1 phosphorylation of the kinetochore protein Nsk1 prevents error-prone chromosome segregation. J Cell Biol, 195(4), 583-93, 2011

Stumpff, J, Du, Y, English, CA, Maliga, Z, Wagenbach, M, Asbury, CL, Wordeman, L, Ohi, R. A Tethering Mechanism Controls the Processivity and Kinetochore-Microtubule Plus-End Enrichment of the Kinesin-8 Kif18A. Mol Cell, 43(5), 764-75, 2011

Du, Y, English, CA, Ohi, R. The kinesin-8 Kif18A dampens microtubule plus-end dynamics. Curr Biol, 20(4), 374-80, 2010

Needleman, DJ, Groen, A, Ohi, R, Maresca, T, Mirny, L, Mitchison, T. Fast microtubule dynamics in meiotic spindles measured by single molecule imaging: evidence that the spindle environment does not stabilize microtubules. Mol Biol Cell, 21(2), 323-33, 2010 PMCID:2808228

Ohi, R. Kip3-ing kinetochores clustered. Cell Cycle, 9(13), 2497, 2010

Maresca, TJ, Groen, AC, Gatlin, JC, Ohi, R, Mitchison, TJ, Salmon, ED. Spindle Assembly in the Absence of a RanGTP Gradient Requires Localized CPC Activity. Curr Biol, 2009 PMCID:2752711

Efimov, A, Schiefermeier, N, Grigoriev, I, Ohi, R, Brown, MC, Turner, CE, Small, JV, Kaverina, I. Paxillin-dependent stimulation of microtubule catastrophes at focal adhesion sites. J Cell Sci, 121(Pt 2), 196-204, 2008

Germane, KL, Ohi, R, Goldberg, MB, Spiller, BW. Structural and functional studies indicate that Shigella VirA is not a protease and does not directly destabilize microtubules. Biochemistry, 47(39), 10241-3, 2008

Coughlin, M, Brieher, WM, Ohi, R. Cell-free extract systems and the cytoskeleton: preparation of biochemical experiments for transmission electron microscopy. Methods Mol Biol, 369, 199-212, 2007

Ohi, R, Burbank, K, Liu, Q, Mitchison, TJ. Nonredundant Functions of Kinesin-13s during Meiotic Spindle Assembly. Curr Biol, 17(11), 953-9, 2007

Groen, AC, Cameron, LA, Coughlin, M, Miyamoto, DT, Mitchison, TJ, Ohi, R. XRHAMM functions in ran-dependent microtubule nucleation and pole formation during anastral spindle assembly. Curr Biol, 14(20), 1801-11, 2004

Mitchison, TJ, Maddox, P, Groen, A, Cameron, L, Perlman, Z, Ohi, R, Desai, A, Salmon, ED, Kapoor, TM. Bipolarization and poleward flux correlate during Xenopus extract spindle assembly. Mol Biol Cell, 15(12), 5603-15, 2004 PMCID:532038

Ohi, R, Sapra, T, Howard, J, Mitchison, TJ. Differentiation of cytoplasmic and meiotic spindle assembly MCAK functions by Aurora B-dependent phosphorylation. Mol Biol Cell, 15(6), 2895-906, 2004 PMCID:420112

Sampath, SC, Ohi, R, Leismann, O, Salic, A, Pozniakovski, A, Funabiki, H. The chromosomal passenger complex is required for chromatin-induced microtubule stabilization and spindle assembly. Cell, 118(2), 187-202, 2004

Ohi, R, Coughlin, ML, Lane, WS, Mitchison, TJ. An inner centromere protein that stimulates the microtubule depolymerizing activity of a KinI kinesin. Dev Cell, 5(2), 309-21, 2003

Burns, CG, Ohi, R, Mehta, S, O'Toole, ET, Winey, M, Clark, TA, Sugnet, CW, Ares, M, Gould, KL. Removal of a single alpha-tubulin gene intron suppresses cell cycle arrest phenotypes of splicing factor mutations in Saccharomyces cerevisiae. Mol Cell Biol, 22(3), 801-15, 2002 PMCID:133559

Burns, CG, Ohi, R, Krainer, AR, Gould, KL. Evidence that Myb-related CDC5 proteins are required for pre-mRNA splicing. Proc Natl Acad Sci U S A, 96(24), 13789-94, 1999 PMCID:24143

Feoktistova, A, McCollum, D, Ohi, R, Gould, KL. Identification and characterization of Schizosaccharomyces pombe asp1(+), a gene that interacts with mutations in the Arp2/3 complex and actin. Genetics, 152(3), 895-908, 1999 PMCID:1460656

McDonald, WH, Ohi, R, Smelkova, N, Frendewey, D, Gould, KL. Myb-related fission yeast cdc5p is a component of a 40S snRNP-containing complex and is essential for pre-mRNA splicing. Mol Cell Biol, 19(8), 5352-62, 1999 PMCID:84378

Ohi, R, Gould, KL. Regulating the onset of mitosis. Curr Opin Cell Biol, 11(2), 267-73, 1999

Ohi, R, Feoktistova, A, McCann, S, Valentine, V, Look, AT, Lipsick, JS, Gould, KL. Myb-related Schizosaccharomyces pombe cdc5p is structurally and functionally conserved in eukaryotes. Mol Cell Biol, 18(7), 4097-108, 1998 PMCID:108994

Ohi, R, Feoktistova, A, Gould, KL. Construction of vectors and a genomic library for use with his3-deficient strains of Schizosaccharomyces pombe. Gene, 174(2), 315-8, 1996

Ohi, R, McCollum, D, Hirani, B, Den Haese, GJ, Zhang, X, Burke, JD, Turner, K, Gould, KL. The Schizosaccharomyces pombe cdc5+ gene encodes an essential protein with homology to c-Myb. EMBO J, 13(2), 471-83, 1994 PMCID:394831

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