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Michael S. Krangel, PhD

Mary Bernheim Professor of Immunology
Campus Mail: 318 Jones Bldg, Durham, NC 27710
Phone: (919) 684-4985
Email: krang001@mc.duke.edu

The process of V(D)J recombination assembles T cell receptor (TCR) genes (α,β,γ,δ) from variable (V), diversity (D) and joining (J) gene segments during T cell development, and is essential for the formation of diverse antigen receptor repertoires on αβ and γδ T lymphocytes. We are interested in the molecular basis for developmentally regulated rearrangement and expression of murine TCR genes. One focus of our studies is the TCRα/δ locus, because it represents an intriguing model with two sets of gene segments that are differentially activated for recombination during T cell development. We are also studying the TCRβ locus, because this locus presents a model in which there is a developmental inactivation of V(D)J recombination associated with the process of allelic exclusion. V(D)J recombination depends on the ability of recombinase proteins RAG1 and RAG2 to recognize and generate double-strand breaks at recombination signal sequences that flank TCR gene segments. Our main focus has been on the role of chromatin structure in defining the portions of these loci that are accessible to the RAG recombinase and therefore active for V(D)J recombination, and on the mechanisms by which cis-regulatory elements within these loci (enhancers, promoters) function as developmental regulators of chromatin structure. Our primary approach has been to manipulate cis-acting elements within these loci by gene targeting, and to study the effects of these manipulations on locus chromatin structure and recombination events in developing thymocytes in vivo. An important outcome of this work has been our demonstration that enhancer- and promoter-directed transcription through recombination signal sequences can displace and covalently modify nucleosomes to provide accessibility for RAG binding and V(D)J recombination.

Recent work in our laboratory and elsewhere has highlighted additional properties of antigen receptor loci that likely to play important roles in developmental regulation. One area of interest is subnuclear positioning. We have used three-dimensional fluorescence in situ hybridization (3D-FISH) to show that TCRβ alleles interact stochastically and at high frequency with the nuclear lamina and with foci of pericentromeric heterochromatin, and that these interactions are inhibitory to V(D)J recombination. We suspect that these inhibitory interactions help to promote allelic exclusion by diminishing the likelihood of simultaneous V to DJ recombination on both alleles. Current work is aimed at developing a better understanding of how the TCRβ locus interacts with the nuclear lamina and the mechanism by which this interaction impacts recombination events.

A second area of interest is locus conformation. It is now appreciated that recombination events at antigen receptor loci depend on locus conformational changes that bring into proximity gene segments that may be widely separated in the linear DNA sequence. Conformational states can be defined using 3D-FISH or a chemical crosslinking approach called chromosome conformation capture (3C). Recent studies indicate that developmental changes in locus conformation contribute to allelic exclusion at the TCRβ locus and mediate a transition from TCRδ to TCRα rearrangement at the TCRα/δ locus. Current work aims to address at a molecular level how locus conformational states are maintained and modified during T cell development and how these changes impact long-distance transactions including enhancer-promoter communication and V(D)J recombination.

Education and Training

  • Ph.D., Harvard University , 1982

Selected Publications

Chan, Elizabeth A. W., Grace Teng, Elizabeth Corbett, Kingshuk Roy Choudhury, Craig H. Bassing, David G. Schatz, and Michael S. Krangel. “Peripheral subnuclear positioning suppresses Tcrb recombination and segregates Tcrb alleles from RAG2..” Proc Natl Acad Sci U S A 110, no. 48 (November 26, 2013): E4628–37. https://doi.org/10.1073/pnas.1310846110.

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Shih, Han-Yu, and Michael S. Krangel. “Chromatin architecture, CCCTC-binding factor, and V(D)J recombination: managing long-distance relationships at antigen receptor loci..” J Immunol 190, no. 10 (May 15, 2013): 4915–21. https://doi.org/10.4049/jimmunol.1300218.

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Callen, Elsa, Robert B. Faryabi, Megan Luckey, Bingtao Hao, Jeremy A. Daniel, Wenjing Yang, Hong-Wei Sun, et al. “The DNA damage- and transcription-associated protein paxip1 controls thymocyte development and emigration..” Immunity 37, no. 6 (December 14, 2012): 971–85. https://doi.org/10.1016/j.immuni.2012.10.007.

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Shih, Han-Yu, Jiyoti Verma-Gaur, Ali Torkamani, Ann J. Feeney, Niels Galjart, and Michael S. Krangel. “Tcra gene recombination is supported by a Tcra enhancer- and CTCF-dependent chromatin hub..” Proc Natl Acad Sci U S A 109, no. 50 (December 11, 2012): E3493–3502. https://doi.org/10.1073/pnas.1214131109.

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Kondilis-Mangum, Hrisavgi D., Han-Yu Shih, Grace Mahowald, Barry P. Sleckman, and Michael S. Krangel. “Regulation of TCRβ allelic exclusion by gene segment proximity and accessibility..” J Immunol 187, no. 12 (December 15, 2011): 6374–81. https://doi.org/10.4049/jimmunol.1102611.

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Seitan, Vlad C., Bingtao Hao, Kikuë Tachibana-Konwalski, Thais Lavagnolli, Hegias Mira-Bontenbal, Karen E. Brown, Grace Teng, et al. “A role for cohesin in T-cell-receptor rearrangement and thymocyte differentiation..” Nature 476, no. 7361 (August 10, 2011): 467–71. https://doi.org/10.1038/nature10312.

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Shih, Han-Yu, Bingtao Hao, and Michael S. Krangel. “Orchestrating T-cell receptor α gene assembly through changes in chromatin structure and organization..” Immunol Res 49, no. 1–3 (April 2011): 192–201. https://doi.org/10.1007/s12026-010-8181-y.

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Carabana, Juan, Akiko Watanabe, Bingtao Hao, and Michael S. Krangel. “A barrier-type insulator forms a boundary between active and inactive chromatin at the murine TCRβ locus..” J Immunol 186, no. 6 (March 15, 2011): 3556–62. https://doi.org/10.4049/jimmunol.1003164.

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Ji, Yanhong, Alicia J. Little, Joydeep K. Banerjee, Bingtao Hao, Eugene M. Oltz, Michael S. Krangel, and David G. Schatz. “Promoters, enhancers, and transcription target RAG1 binding during V(D)J recombination..” J Exp Med 207, no. 13 (December 20, 2010): 2809–16. https://doi.org/10.1084/jem.20101136.

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Shih, Han-Yu, and Michael S. Krangel. “Distinct contracted conformations of the Tcra/Tcrd locus during Tcra and Tcrd recombination..” J Exp Med 207, no. 9 (August 30, 2010): 1835–41. https://doi.org/10.1084/jem.20100772.

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Kondilis-Mangum, Hrisavgi D., Robin Milley Cobb, Oleg Osipovich, Sruti Srivatsan, Eugene M. Oltz, and Michael S. Krangel. “Transcription-dependent mobilization of nucleosomes at accessible TCR gene segments in vivo..” J Immunol 184, no. 12 (June 15, 2010): 6970–77. https://doi.org/10.4049/jimmunol.0903923.

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