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Outline of our achievements

Laboratory of Cell Engineering

About our research

Purpose of our research

 Chromosomes are propagated accurately during the process of cell proliferation. Histones and a large number of functional proteins assemble on genomic DNA to build chromatin structures and, ultimately, the chromosomes themselves (46 pairs in human cells). The expression of each of the 23,000 genes arranged on the 46 human chromosomes is modulated by chromatin proteins and their epigenetic modifications. Thus, these proteins play crucial roles in the development and differentiation processes that are responsible for generating various cellular characteristics. Our research focuses on elucidating the mechanisms by which the functional structure of the chromosome is established and maintained through interactions between chromosomal proteins and DNA.

Characteristics of our research

 The centromere/kinetochore is the chromosomal structure responsible for chromosome segregation during cell division. We cloned a long repetitive DNA sequence from a human centromere, and then introduced this cloned repetitive DNA (or various engineered synthetic versions) into cultured human cells to generate an artificial mini-chromosome (the 47th chromosome) with full centromere function. This Human Artificial Chromosome (HAC) has several advantages for the dissection, reconstruction, and manipulation of molecular structures and mechanisms related to chromosome dynamics, particularly centromere/kinetochore structure. Our laboratory has been investigating the molecular mechanisms by which centromeric chromatin influences the establishment and maintenance of proper segregation.

Expected fields of application

 To achieve further progress in the life and medical sciences, it is important to make full use of the enormous amount of human genomic information. Our HAC stably propagates as an extra mini-chromosome. Furthermore, the HAC can harbor multiple inserted genes, whose expression can be controlled either naturally or by artificial manipulation. Our other major goal is to develop next-generation HACs and HAC vector systems for gene delivery, protein production, and transgenic animal production.

Our research projects

  1. Elucidation of Chromosome Functions
  2. We are investigating how proteins assemble on synthetic DNAs newly introduced into human and mouse cells, how the centromere/kinetochore and artificial chromosomes are assembled and maintained (along with the input DNAs) throughout the cell proliferation process, and how the on/off status of genes is affected by chromosomal structure.

  3. Development of a gene delivery system using a self-removable HAC
  4. If a HAC containing active genes is capable of being transferred into any cell, but is also capable of being removed when no longer required, then the safety of gene therapy and iPS cell production would be greatly improved because the risk of damaging the patient's own genomic DNA would be reduced. We have already developed a HAC whose centromere activity can be specifically suppressed, and which is therefore auto-removable. We are now making further improvements to the auto-removable HAC vector system and the HAC transfer methods used for gene delivery.

  5. Development of transgenic animal production technology using a HAC system
  6. We introduced multiple large human genes into a HAC; subsequently, via HAC transfer into ES cells, we generated transgenic mice that retained the HAC and the inserted human genes. We would like to use these mice as models of human disease for basic medical research.


Hiroshi Masumotothe head of a laboratory masumoto at kazusa.or.jp
Koei Okazaki senior researcher kokazaki at kazusa.or.jp
Junichiro Ozeki research staff johzeki at kazusa.or.jp
Kazuto Kugo research staff kkugou at kazusa.or.jp
Takafumi Narise special researcher narise at kazusa.or.jp



Shugoshin forms a specialized chromatin domain at subtelomeres that regulates transcription and replication timing.
Tashiro S, Handa T, Matsuda A, Ban T, Takigawa T, Miyasato K, Ishii K, Kugou K, Ohta K, Hiraoka Y, Masukata H, Kanoh J.
Nat Commun. 7: 10393. (2016)

Analysis of novel Sir3 binding regions in Saccharomyces cerevisiae.
Mitsumori R, Ohashi T, Kugou K, Ichino A, Taniguchi K, Ohta K, Uchida H, Oki M.
J Biochem. 160 (1): 11 - 17. (2016)

Development of a novel HAC-based "gain of signal" quantitative assay for measuring chromosome instability (CIN) in cancer cells.
Kim JH, Lee HS, Lee NC, Goncharov NV, Kumeiko V, Masumoto H, Earnshaw WC, Kouprina N, Larionov V.
Oncotarget. 7 (12): 14841 - 14856. (2016)

CENP-B box, a nucleotide motif involved in centromere formation, occurs in a New World monkey.
Suntronpong A, Kugou K, Masumoto H, Srikulnath K, Ohshima K, Hirai H, Koga A.
Biol. Lett. 12 (3): 20150817. (2016)

KAT7/HBO1/MYST2 regulates CENP-A chromatin assembly by antagonizing Suv39h1-mediated centromere inactivation.
Ohzeki J, Shono N, Otake K, Martins NMC, Kugou K, Kimura H, Nagase T, Larionov V, Earnshaw WC, Masumoto H.
Dev Cell. 37 (5): 413 - 427. (2016)

Formation of functional CENP-B boxes at diverse locations in repeat units of centromeric DNA in New World monkeys.
Kugou K, Hirai H, Masumoto H, Koga A.
Sci Rep. 6: 27833. (2016)

3D-CLEM reveals that a major portion of mitotic chromosomes is not chromatin.
Booth DG, Beckett AJ, Molina O, Samejima I, Masumoto H, Kouprina N, Larionov V, Prior IA, Earnshaw WC.
Mol Cell. 64 (4): 790-802. (2016)

Epigenetic engineering reveals a balance between histone modifications and transcription in kinetochore maintenance.
Molina O, Vargiu G, Abad MA, Zhiteneva A, Jeyaprakash AA, Masumoto H, Kouprina N, Larionov V, Earnshaw WC.
Nat Commun. 7: 13334. (2016)

CENP-C and CENP-I are key connecting factors for kinetochore and CENP-A assembly.
Shono N, Ohzeki J, Otake K, Martins NMC, Nagase T, Kimura H, Larionov V, Earnshaw WC, Masumoto H.

J. Cell Science 128(24):4572-4587. (2015)

Stable complex formation of CENP-B with the CENP-A nucleosome.
Fujita R#, Otake K#, Arimura Y, Horikoshi N, Miya Y, Shiga T, Osakabe A, Tachiwana H, Ohzeki J, Larionov V, Masumoto H*, and Kurumizaka H. 
# equally contributed.
Nucleic Acids Res. 43(10): 4909-4922 (2015)

Genetic and epigenetic regulation of centromeres: A look at HAC formation.
Ohzeki J, Larionov V, Earnshaw WC, and Masumoto H.
Chromosome Res. 23: 87-103 (2015)

Generation of a conditionally self-eliminating HAC gene delivery vector through incorporation of a tTAVP64 expression cassette.
Kononenko A, Lee NC, Liskovykh M, Masumoto H, Earnshaw WC, Larionov V, Kouprina N.
Nucleic Acids Res. 43 (9): e57. (2015)

Generating a transgenic mouse line stably expressing human MHC surface antigen from a HAC carrying multiple genomic BACs.
Hasegawa Y, Ishikura T, Hasegawa T, Watanabe T, Suzuki J, Nakayama M, Okamura Y, Okazaki T, Koseki H, Ohara O, Ikeno M, and Masumoto H. Chromosoma 124(1): 107-118 (2015) [Epub ahead of print 2014]

Replication of alpha-satellite DNA arrays in endogenous human centromeric regions and in human artificial chromosome. 
Erliandri I, Fu H, Nakano M, Kim JH, Miga KH, Liskovykh M, Earnshaw WC, Masumoto H, Kouprina N, Aladjem MI, Larionov V.
Nucleic Acids Res. 42(18): 11502-11516 (2015) [Epub ahead of print 2014]

A portable BRCA1-HAC (human artificial chromosome) module for analysis of BRCA1 tumor suppressor function. 
Kononenko AV, Bansal R, Lee NC, Grimes BR, Masumoto H, Earnshaw WC, Larionov V, Kouprina N.
Nucleic Acids Res. 42(21): e164 (2014)

The epigenetic regulator Uhrf1 facilitates the proliferation and maturation of colonic regulatory T cells.
Obata Y, Furusawa Y, Endo TA, Sharif J, Takahashi D, Atarashi K, Nakayama M, Onawa S, Fujimura Y, Takahashi M, Ikawa T, Otsubo T, Kawamura YI, Dohi T, Tajima S, Masumoto H, Ohara O, Honda K, Hori S, Ohno H, Koseki H, Hase K.
Nat Immunol. 15(6): 571-579 (2014)

Human artificial chromosome based gene delivery vectors for biomedicine and biotechnology.
Kouprina N, Tomilin AN, Masumoto H, Earnshaw WC, Larionov V.
Expert Opin. Drug Deliv. 11(4):517-35 (2014)

Identification of novel α-n-methylation of CENP-B that regulates its binding to the centromeric DNA.
Dai X, Otake K, You C, Cai Q, Wang Z, Masumoto H, Wang Y.
J Proteome Res. 12(9): 4167-75. (2013)

A new generation of human artificial chromosomes for functional genomics and gene therapy.
Kouprina N, Earnshaw WC, Masumoto H, Larionov V.
Cell Mol Life Sci. 70(7): 1135-1148. (2013)

A new assay for measuring chromosome instability (CIN) and identification of drugs that elevate CIN in cancer cells.
Lee HS, Lee NC, Grimes BR, Samoshkin A, Kononenko AV, Bansal R, Masumoto H, Earnshaw WC, Kouprina N, Larionov V.
BMC Cancer 13: 252. (2013)

Protecting a transgene expression from the HAC-based vector by different chromatin insulators.
Lee NC, Kononenko AV, Lee HS, Tolkunova EN, Liskovykh MA, Masumoto H, Earnshaw WC, Tomilin AN, Larionov V, Kouprina N.
Cell Mol Life Sci. 70(19): 3723-3737. (2013)

Esperanto for histones: CENP-A, not CenH3, is the centromeric histone H3 variant.
Earnshaw WC, Allshire RC, Black BE, Bloom K, Brinkley BR, Brown W, Cheeseman IM, Choo KH, Copenhaver GP, Deluca JG, Desai A, Diekmann S, Erhardt S, Fitzgerald-Hayes M, Foltz D, Fukagawa T, Gassmann R, Gerlich DW, Glover DM, Gorbsky GJ, Harrison SC, Heun P, Hirota T, Jansen LE, Karpen G, Kops GJ, Lampson MA, Lens SM, Losada A, Luger K, Maiato H, Maddox PS, Margolis RL, Masumoto H, McAinsh AD, Mellone BG, Meraldi P, Musacchio A, Oegema K, O'Neill RJ, Salmon ED, Scott KC, Straight AF, Stukenberg PT, Sullivan BA, Sullivan KF, Sunkel CE, Swedlow JR, Walczak CE, Warburton PE, Westermann S, Willard HF, Wordeman L, Yanagida M, Yen TJ, Yoda K, Cleveland DW.
Chromosome Res. 21(2): 101-106. (2013)

Nap1 regulates proper CENP-B binding to nucleosomes.
Tachiwana H, Miya Y, Shono N, Ohzeki J, Osakabe A, Otake K, Larionov V, Earnshaw WC, Kimura H, Masumoto H, Kurumizaka H.
Nucleic Acids Res. 41(5): 2869-2880. (2013)
Centromere Architecture Breakdown Induced by the Viral E3 Ubiquitin Ligase ICP0 Protein of Herpes Simplex Virus Type 1.
Gross S, Catez F, Masumoto H, Lomonte P.
PLOS ONE, 7(9): e44227. (2012)

Organization of Synthetic Alphoid DNA Array in Human Artifcial Chromosome (HAC) with a Conditional Centromere.。。
Kouprina N, Samoshkin A, Erliandri I, Nakano M, Lee H-S, Fu H, Iida Y, Aladjem M, Oshimura M, Masumoto M, Earnshaw WC, Larionov V.
ACS Synth.Biol. 1(12): 590-601. (2012)

Breaking the HAC Barrier: histone H3K9 acetyl/methyl balance regulates CENP-A assembly.
Ohzeki J, Bergmann JH, Kouprina N, Noskov VN, Nakano M, Kimura H, Earnshaw WC, Larionov V, Masumoto H.
EMBO J. 31(10): 2391-2402. (2012)

Epigenetic engineering: histone H3K9 acetylation is compatible with kinetochore structure and function.
Bergmann JH, Jakubsche JN, Martins NM, Kagansky A, Nakano M, Kimura H, Kelly DA, Turner BM, Masumoto H, Larionov V, Earnshaw WC.
J Cell Sci. 125(Pt 2): 411-421. (2012)

A new generation of human artificial chromosomes for functional genomics and gene therapy.
Kouprina N, Earnshaw WC, Masumoto H, Larionov V.
Cell. Mol. Life Sci. 70(7):1135-48 (2012)

HACking the centromere chromatin code: insights from human artificial chromosomes.
Bergmann JH, Martins NM, Larionov V, Masumoto H, Earnshaw WC.
Chromosome Res. 20(5): 505-519, (2012)

Human artificial chromosome (HAC) vector with a conditional centromere for correction of genetic deficiencies in human cells.
Kim JH, Kononenko A, Erliandri I, Kim TA, Nakano M, Iida Y, Barrett JC, Oshimura M, Masumoto H, Earnshaw WC, Larionov V, Kouprina N.
Proc Natl Acad Sci U S A. 108(50): 20048-20053. (2011)

HP1 gamma links histone methylation marks to meiotic synapsis in mice.
Takada Y, Naruse C, Costa Y, Shirakawa T, Tachibana M, Sharif J, Kezuka-Shiotani F, Kakiuchi D, Masumoto H, Shinkai Y, Ohbo K, Peters AH, Turner JM, Asano M, Koseki H. (2011)
Development 138(19): 4207-4217.

Epigenetic engineering shows H3K4me2 is required for HJURP targeting and CENP-A assembly on a synthetic human kinetochore.
Bergmann JH, Rodriguez MG, Martins NM, Kimura H, Kelly DA, Masumoto H, Larionov V, Jansen LE, Earnshaw WC.
EMBO J. 30(2): 328-340. (2011)

Human Artificial Chromosome with a Conditional Centromere for Gene Delivery and Gene Expression.
Iida Y, Kim JH, Kazuki Y, Hoshiya H, Takiguchi M, Hayashi M, Erliandri I, Lee HS, Samoshkin A, Masumoto H, Earnshaw WC, Kouprina N, Larionov V, Oshimura M.
DNA Res. 17(5): 293-301. (2010)

Hierarchical inactivation of a synthetic human kinetochore by a chromatin modifier.
Cardinale S, Bergmann JH, Kelly D, Nakano M, Valdivia MM, Kimura H, Masumoto H, Larionov V, Earnshaw WC.
Mol Biol Cell 20(19): 4194-4204. (2009)

Human gamma-satellite DNA maintains open chromatin structure and protects a transgene from epigenetic silencing.
Kim JH, Ebersole T, Kouprina N, Noskov VN, Ohzeki J, Masumoto H, Mravinac B, Sullivan BA., Pavlicek A, Dovat S, Pack SD, Kwon YW, Flanagan PT, Loukinov D, Lobanenkov V, Larionov V.
Genome Res. 19(4): 533-544. (2009)

Inactivation of a human kinetochore by specific targeting of chromatin modifiers.
Nakano M, Cardinale S, Noskov V, Gassmann R, Vagnarelli P, Kandels-Lewis S, Larionov V, Earnshaw WC, Masumoto H.
Developmental Cell 14(4): 507-522. (2008)

Human Artificial Centromeres: De novo assembly of functional centromeres on human artificial chromosomes.
Masumoto H, Okada T, Okamoto Y.
In "The Kinetochore: from Molecular Discoveries to Cancer Therapy".
Eds. De Wulf P and Earnshaw WC. Springer Publ. New York. pp. 107-132. (2008)

CENP-B controls centromere formation depending on the chromatin context.
Okada T, Ohzeki J, Nakano M, Yoda K, Brinkley WR, Larionov V, Masumoto H.
Cell.131(7): 1287-1300. (2007)

A minimal CENP-A core is required for nucleation and maintenance of a functional human centromere.
Okamoto Y, Nakano M, Ohzeki J, Larionov V, Masumoto H.
EMBO J. 26: 1279-1291. (2007)