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Doddihal V, Mann FG, Ross EJ, McKinney MC, Guerrero-Hernández C, Brewster CE, McKinney SA, Sánchez Alvarado A. A PAK family kinase and the Hippo/Yorkie pathway modulate WNT signaling to functionally integrate body axes during regeneration. Proc Natl Acad Sci U S A 2024; 121:e2321919121. [PMID: 38713625 PMCID: PMC11098123 DOI: 10.1073/pnas.2321919121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 04/03/2024] [Indexed: 05/09/2024] Open
Abstract
Successful regeneration of missing tissues requires seamless integration of positional information along the body axes. Planarians, which regenerate from almost any injury, use conserved, developmentally important signaling pathways to pattern the body axes. However, the molecular mechanisms which facilitate cross talk between these signaling pathways to integrate positional information remain poorly understood. Here, we report a p21-activated kinase (smed-pak1) which functionally integrates the anterior-posterior (AP) and the medio-lateral (ML) axes. pak1 inhibits WNT/β-catenin signaling along the AP axis and, functions synergistically with the β-catenin-independent WNT signaling of the ML axis. Furthermore, this functional integration is dependent on warts and merlin-the components of the Hippo/Yorkie (YKI) pathway. Hippo/YKI pathway is a critical regulator of body size in flies and mice, but our data suggest the pathway regulates body axes patterning in planarians. Our study provides a signaling network integrating positional information which can mediate coordinated growth and patterning during planarian regeneration.
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Affiliation(s)
- Viraj Doddihal
- Stowers Institute for Medical Research, Kansas City, MO64110
| | | | - Eric J. Ross
- Stowers Institute for Medical Research, Kansas City, MO64110
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2
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Chen JJ, Lei K. The known, unknown, and unknown unknowns of cell-cell communication in planarian regeneration. Zool Res 2023; 44:981-992. [PMID: 37721107 PMCID: PMC10559094 DOI: 10.24272/j.issn.2095-8137.2023.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 09/11/2023] [Indexed: 09/19/2023] Open
Abstract
Planarians represent the most primitive bilateral triploblastic animals. Most planarian species exhibit mechanisms for whole-body regeneration, exemplified by the regeneration of their cephalic ganglion after complete excision. Given their robust whole-body regeneration capacity, planarians have been model organisms in regenerative research for more than 240 years. Advancements in research tools and techniques have progressively elucidated the mechanisms underlying planarian regeneration. Accurate cell-cell communication is recognized as a fundamental requirement for regeneration. In recent decades, mechanisms associated with such communication have been revealed at the cellular level. Notably, stem cells (neoblasts) have been identified as the source of all new cells during planarian homeostasis and regeneration. The interplay between neoblasts and somatic cells affects the identities and proportions of various tissues during homeostasis and regeneration. Here, this review outlines key discoveries regarding communication between stem cell compartments and other cell types in planarians, as well as the impact of communication on planarian regeneration. Additionally, this review discusses the challenges and potential directions of future planarian research, emphasizing the sustained impact of this field on our understanding of animal regeneration.
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Affiliation(s)
- Jia-Jia Chen
- School of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310030, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Kai Lei
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310030, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China. E-mail:
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3
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Hulett RE, Kimura JO, Bolaños DM, Luo YJ, Rivera-López C, Ricci L, Srivastava M. Acoel single-cell atlas reveals expression dynamics and heterogeneity of adult pluripotent stem cells. Nat Commun 2023; 14:2612. [PMID: 37147314 PMCID: PMC10163032 DOI: 10.1038/s41467-023-38016-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 04/11/2023] [Indexed: 05/07/2023] Open
Abstract
Adult pluripotent stem cell (aPSC) populations underlie whole-body regeneration in many distantly-related animal lineages, but how the underlying cellular and molecular mechanisms compare across species is unknown. Here, we apply single-cell RNA sequencing to profile transcriptional cell states of the acoel worm Hofstenia miamia during postembryonic development and regeneration. We identify cell types shared across stages and their associated gene expression dynamics during regeneration. Functional studies confirm that the aPSCs, also known as neoblasts, are the source of differentiated cells and reveal transcription factors needed for differentiation. Subclustering of neoblasts recovers transcriptionally distinct subpopulations, the majority of which are likely specialized to differentiated lineages. One neoblast subset, showing enriched expression of the histone variant H3.3, appears to lack specialization. Altogether, the cell states identified in this study facilitate comparisons to other species and enable future studies of stem cell fate potentials.
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Affiliation(s)
- Ryan E Hulett
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA, 02138, USA
| | - Julian O Kimura
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA, 02138, USA
| | - D Marcela Bolaños
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA, 02138, USA
| | - Yi-Jyun Luo
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA, 02138, USA
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Carlos Rivera-López
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA, 02138, USA
- Department of Molecular and Cell Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Lorenzo Ricci
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA, 02138, USA
| | - Mansi Srivastava
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA, 02138, USA.
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4
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Kaethner M, Epping K, Bernthaler P, Rudolf K, Thomann I, Leitschuh N, Bergmann M, Spiliotis M, Koziol U, Brehm K. Transforming growth factor-β signalling regulates protoscolex formation in the Echinococcus multilocularis metacestode. Front Cell Infect Microbiol 2023; 13:1153117. [PMID: 37033489 PMCID: PMC10073696 DOI: 10.3389/fcimb.2023.1153117] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 02/23/2023] [Indexed: 04/11/2023] Open
Abstract
The lethal zoonosis alveolar echinococcosis (AE) is caused by tumor-like, infiltrative growth of the metacestode larval stage of the tapeworm Echinococcus multilocularis. We previously showed that the metacestode is composed of posteriorized tissue and that the production of the subsequent larval stage, the protoscolex, depends on re-establishment of anterior identities within the metacestode germinative layer. It is, however, unclear so far how protoscolex differentiation in Echinococcus is regulated. We herein characterized the full complement of E. multilocularis TGFβ/BMP receptors, which is composed of one type II and three type I receptor serine/threonine kinases. Functional analyzes showed that all Echinococcus TGFβ/BMP receptors are enzymatically active and respond to host derived TGFβ/BMP ligands for activating downstream Smad transcription factors. In situ hybridization experiments demonstrated that the Echinococcus TGFβ/BMP receptors are mainly expressed by nerve and muscle cells within the germinative layer and in developing brood capsules. Interestingly, the production of brood capsules, which later give rise to protoscoleces, was strongly suppressed in the presence of inhibitors directed against TGFβ/BMP receptors, whereas protoscolex differentiation was accelerated in response to host BMP2 and TGFβ. Apart from being responsive to host TGFβ/BMP ligands, protoscolex production also correlated with the expression of a parasite-derived TGFβ-like ligand, EmACT, which is expressed in early brood capsules and which is strongly expressed in anterior domains during protoscolex development. Taken together, these data indicate an important role of TGFβ/BMP signalling in Echinococcus anterior pole formation and protoscolex development. Since TGFβ is accumulating around metacestode lesions at later stages of the infection, the host immune response could thus serve as a signal by which the parasite senses the time point at which protoscoleces must be produced. Overall, our data shed new light on molecular mechanisms of host-parasite interaction during AE and are relevant for the development of novel treatment strategies.
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Affiliation(s)
- Marc Kaethner
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Kerstin Epping
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Peter Bernthaler
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Kilian Rudolf
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Irena Thomann
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Nadine Leitschuh
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
- Laboratory of Microbiology and Biotechnology, Department of Food Technology, Fulda University of Applied Sciences, Fulda, Germany
| | - Monika Bergmann
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Markus Spiliotis
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Uriel Koziol
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
- Sección Biología Celular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Klaus Brehm
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
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Wnt/β-catenin signalling is required for pole-specific chromatin remodeling during planarian regeneration. Nat Commun 2023; 14:298. [PMID: 36653403 PMCID: PMC9849279 DOI: 10.1038/s41467-023-35937-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 01/09/2023] [Indexed: 01/19/2023] Open
Abstract
For successful regeneration, the identity of the missing tissue must be specified according to the pre-existing tissue. Planarians are ideal for the study of the mechanisms underlying this process; the same field of cells can regrow a head or a tail according to the missing body part. After amputation, the differential activation of the Wnt/β-catenin signal specifies anterior versus posterior identity. Initially, both wnt1 and notum (Wnt inhibitor) are expressed in all wounds, but 48 hours later they are restricted to posterior or anterior facing wounds, respectively, by an unknown mechanism. Here we show that 12 hours after amputation, the chromatin accessibility of cells in the wound region changes according to the polarity of the pre-existing tissue in a Wnt/β-catenin-dependent manner. Genomic analyses suggest that homeobox transcription factors and chromatin-remodeling proteins are direct Wnt/β-catenin targets, which trigger the expression of posterior effectors. Finally, we identify FoxG as a wnt1 up-stream regulator, probably via binding to its first intron enhancer region.
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6
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Petersen CP. Wnt signaling in whole-body regeneration. Curr Top Dev Biol 2023; 153:347-380. [PMID: 36967200 DOI: 10.1016/bs.ctdb.2023.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Regeneration abilities are widespread among animals and select species can restore any body parts removed by wounds that sever the major body axes. This capability of whole-body regeneration as exemplified in flatworm planarians, Acoels, and Cnidarians involves initial responses to injury, the assessment of wound site polarization, determination of missing tissue and programming of blastema fate, and patterned outgrowth to restore axis content and proportionality. Wnt signaling drives many shared and conserved aspects of the biology of whole-body regeneration in the planarian species Schmidtea mediterranea and Dugesia japonica, in the Acoel Hofstenia miamia, and in Cnidarians Hydra and Nematostella. These overlapping mechanisms suggest whole-body regeneration might be an ancestral property across diverse animal taxa.
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Affiliation(s)
- Christian P Petersen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, United States; Robert Lurie Comprehensive Cancer Center, Northwestern University, Evanston, IL, United States.
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7
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Gittin DI, Petersen CP. A Wnt11 and Dishevelled signaling pathway acts prior to injury to control wound polarization for the onset of planarian regeneration. Curr Biol 2022; 32:5262-5273.e2. [PMID: 36495871 PMCID: PMC9901562 DOI: 10.1016/j.cub.2022.10.071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 09/20/2022] [Accepted: 10/27/2022] [Indexed: 12/13/2022]
Abstract
Regeneration is initiated by wounding, but it is unclear how injury-induced signals precisely convey the identity of the tissues requiring replacement. In the planarian Schmidtea mediterranea, the first event in head regeneration is the asymmetric activation of the Wnt inhibitor notum in longitudinal body-wall muscle cells, preferentially at anterior-facing versus posterior-facing wound sites. However, the mechanism driving this early symmetry-breaking event is unknown. We identify a noncanonical Wnt11 and Dishevelled pathway regulating notum polarization, which opposes injury-induced notum-activating Wnt/β-catenin signals and regulates muscle orientation. Using expression analysis and experiments to define a critical time of action, we demonstrate that Wnt11 and Dishevelled signals act prior to injury and in a growth-dependent manner to orient the polarization of notum induced by wounding. In turn, injury-induced notum dictates polarization used in the next round of regeneration. These results identify a self-reinforcing feedback system driving the polarization of blastema outgrowth and indicate that regeneration uses pre-existing tissue information to determine the outcome of wound-induced signals.
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Affiliation(s)
- David I Gittin
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Christian P Petersen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA; Robert Lurie Comprehensive Cancer Center, Northwestern University, Evanston, IL 60208, USA.
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8
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Bölük A, Yavuz M, Demircan T. Axolotl: A resourceful vertebrate model for regeneration and beyond. Dev Dyn 2022; 251:1914-1933. [PMID: 35906989 DOI: 10.1002/dvdy.520] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/04/2022] [Accepted: 07/21/2022] [Indexed: 01/30/2023] Open
Abstract
The regenerative capacity varies significantly among the animal kingdom. Successful regeneration program in some animals results in the functional restoration of tissues and lost structures. Among the highly regenerative animals, axolotl provides multiple experimental advantages with its many extraordinary characteristics. It has been positioned as a regeneration model organism due to its exceptional renewal capacity, including the internal organs, central nervous system, and appendages, in a scar-free manner. In addition to this unique regeneration ability, the observed low cancer incidence, its resistance to carcinogens, and the reversing effect of its cell extract on neoplasms strongly suggest its usability in cancer research. Axolotl's longevity and efficient utilization of several anti-aging mechanisms underline its potential to be employed in aging studies.
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Affiliation(s)
- Aydın Bölük
- School of Medicine, Muğla Sıtkı Koçman University, Muğla, Turkey
| | - Mervenur Yavuz
- Institute of Health Sciences, Muğla Sıtkı Koçman University, Muğla, Turkey
| | - Turan Demircan
- Department of Medical Biology, School of Medicine, Muğla Sıtkı Koçman University, Muğla, Turkey
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9
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Reddien PW. Positional Information and Stem Cells Combine to Result in Planarian Regeneration. Cold Spring Harb Perspect Biol 2022; 14:a040717. [PMID: 34518341 PMCID: PMC9121904 DOI: 10.1101/cshperspect.a040717] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The capacity for regeneration is broad in the animal kingdom. Planarians are flatworms that can regenerate any missing body part and their regenerative powers have combined with ease of experimentation to make them a classic regeneration model for more than a century. Pluripotent stem cells called neoblasts generate missing planarian tissues. Fate specification happens in the neoblasts, and this can occur in response to regeneration instructions in the form of positional information. Fate specification can lead to differentiating cells in single steps rather than requiring a long lineage hierarchy. Planarians display constitutive expression of positional information from muscle cells, which is required for patterned maintenance of tissues in tissue turnover. Amputation leads to the rapid resetting of positional information in a process triggered by wound signaling and the resetting of positional information is required for regeneration. These findings suggest a model for planarian regeneration in which adult positional information resets after injury to regulate stem cells to bring about the replacement of missing parts.
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Affiliation(s)
- Peter W Reddien
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA
- Department of Biology, MIT, Cambridge, Massachusetts 02139, USA
- Department of Biology, MIT, Cambridge, Massachusetts 02139, USA
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10
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Bonar NA, Gittin DI, Petersen CP. Src acts with WNT/FGFRL signaling to pattern the planarian anteroposterior axis. Development 2022; 149:274880. [PMID: 35297964 PMCID: PMC8995084 DOI: 10.1242/dev.200125] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 03/03/2022] [Indexed: 01/18/2023]
Abstract
Tissue identity determination is crucial for regeneration, and the planarian anteroposterior (AP) axis uses positional control genes expressed from body wall muscle to determine body regionalization. Canonical Wnt signaling establishes anterior versus posterior pole identities through notum and wnt1 signaling, and two Wnt/FGFRL signaling pathways control head and trunk domains, but their downstream signaling mechanisms are not fully understood. Here, we identify a planarian Src homolog that restricts head and trunk identities to anterior positions. src-1(RNAi) animals formed enlarged brains and ectopic eyes and also duplicated trunk tissue, similar to a combination of Wnt/FGFRL RNAi phenotypes. src-1 was required for establishing territories of positional control gene expression in Schmidtea mediterranea, indicating that it acts at an upstream step in patterning the AP axis. Double RNAi experiments and eye regeneration assays suggest src-1 can act in parallel to at least some Wnt and FGFRL factors. Co-inhibition of src-1 with other posterior-promoting factors led to dramatic patterning changes and a reprogramming of Wnt/FGFRLs into controlling new positional outputs. These results identify src-1 as a factor that promotes robustness of the AP positional system that instructs appropriate regeneration.
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Affiliation(s)
- Nicolle A Bonar
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - David I Gittin
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Christian P Petersen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.,Robert Lurie Comprehensive Cancer Center, Northwestern University, Evanston, IL 60208, USA
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11
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Abstract
Stem cell niches are well-characterized factories of signaling information, but niche cells themselves also rely on their neighbors for fate maintenance. In this issue of Developmental Cell, Herrera et al. reveal bi-directional communication between Drosophila testis niche "hub" cells and somatic cyst stem cells.
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Affiliation(s)
- Amelie A Raz
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA; Howard Hughes Medical Institute, Cambridge, MA, USA.
| | - Yukiko M Yamashita
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA; Howard Hughes Medical Institute, Cambridge, MA, USA; Massachusetts Institute of Technology, Cambridge, MA, USA.
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