A5 - Kalcheim

The neural crest (NC) is a transient group of progenitors present in vertebrate embryos. Its component cells yield an extensive variety of derivatives such as melanocytes, neurons of many kinds, glial, ectomesenchymal and endocrine cells. Initially, presumptive NC cells are an integral part of the neuroepithelium. Subsequently, a time and axial level-specific conversion from an epithelial to a mesenchymal (EMT) state causes the cells to become motile and engage in migration. Mesenchymal NC cells then advance through stereotyped pathways, reach their homing sites and then differentiate. The molecular network underlying NC delamination and the generation of cell movement remained incompletely understood. In previous studies, we found that a balance between BMP and its inhibitor noggin underlies the emigration of NC independently of earlier cell specification. BMP induces delamination by triggering Wnt1 transcription. Canonical Wnt signaling promotes G1/S transition which is a necessary step for delamination of trunk NC. Successful delamination also requires the activity of effector genes that act on re-organisation of the actin cytoskeleton and alterations in adhesive properties. In this context, we found that both N-cadherin and RhoGTPase signaling play a negative modulatory role on the process.

During the course of our work, we observed that in the trunk, NC cells continuously delaminate from the NT for over two days, raising the fundamental question of the source and mechanisms accounting for the production of successive waves of NC progenitors. We found that the first NC to delaminate reside in the dorsal midline of the NT and generate sympathetic ganglia, and successive waves translocate ventrodorsally in the NT to replenish the dorsal midline and then delaminate. Hence, the dorsal midline is a dynamic region traversed sequentially by progenitors that colonize NC derivatives in a ventral to dorsal order (chromaffin cells, sympathetic ganglia, then Schwann cells, DRG and finally melanocytes). Based on our data invoking a dynamic behavior of premigratory NC cells, we hypothesize the existence of a dynamic spatiotemporal fate map of derivatives present already within the NT. We aim here at characterizing such a fate map by lineage tracing discrete cell subsets both in time and space. Preliminary data suggest the existence of such a map as well as of a fate restriction of premigratory cells to generate single derivatives. Then, we will aim at elucidating the putative molecular code underlying specification to the various fates. Furthermore, we will investigate the relationship between cell specification and cell migration by asking whether commitment to a certain fate conveys the cell with knowledge regarding the migratory pathway it will follow and consequently, its homing site, or alternatively, whether these are separable and distinctly regulated events. Finally, we propose to investigate whether in addition to its role on NC EMT, N-cadherin plays an earlier role in fate specification of NC cells. Preliminary data suggest that  N-cadherin-mediated adhesion is necessary for initial transcription of some NC-specifier genes and in their absence, NC cells change their migratory pathways and their fate.

Experiments will be performed in avian embryos using in vivo and tissue explant approaches in combination with molecular, microsurgical  and immunohistochemical techniques. Vectors carrying relevant genes for overexpression and inactivation purposes and DNA-based RNAi’s will be electroporated into hemi-or dorsal- neural tubes. This will be followed by analysis of NC delamination in relation to gene expression and mapping of migratory pathways. Fate mapping of the NC will be achieved by iontophoretic delivery and/or focal electroporation of lineage tracers combined with molecular analysis

Die Generierung von Neuralleistenzellen, der Beginn und das Ende ihrer Auswanderung aus der Anlage des ZNS sind Schlüsselprozesse in der Entwicklung des peripheren Nervensystems. Unser Projekt versucht, die zellulären und molekularen Grundlagen der Zellspezifizierung im Kontext von Delaminierung, Committment-Status von prämigratorischen Neuralleisten-Subpopulationen, und der Beziehung zwischen Zellspezifizierung und Determinierung selektiver Migrationswege zu verstehen

Own project-related publications since the last application (2005)

Burstyn-Cohen, T., Stanleigh, J., Sela-Donenfeld, D and Kalcheim, C (2004). Canonical Wnt activity regulates neural crest delamination linking BMP/Noggin signaling with G1/S transition. Development 131: 5327-5339.

Shoval, I, Ludwig, A and Kalcheim, C. (2007) Antagonistic roles for full-length N-cadherin and its BMP-mediated cleavage product in regulating neural crest delamination. Development 134: 491-501.

Ernsberger, U, Esposito, L, Partimo, S, Huber, K, Franke, A, Bixby, J.L., Kalcheim, C and Unsicker, K (2005). Expression of neuronal markers suggests heterogeneity of chick sympathoadrenal cells prior to invasion of the adrenal anlagen. Cell Tissue Res. 319: 1-13.

Gut, P., Huber, K., Lohr, J., Brühl, B., Oberle, S., Treier, M., Ernsberger, U., Kalcheim, C, and Unsicker, K. (2005). Lack of an adrenal cortex in sf1 mutant mice is compatible with generation and differentiation of chromaffin cells. Development 132:4611-4619.

Kalcheim, C. (2005) Vertebrate Embryo: Patterning the Neural Crest Lineage. In: Encyclopedia of Life Sciences. Chichester: John Wiley & Sons, Ltd. http:// www.els.net/ [doi: 10.1038/npg.els.0004212].

Kalcheim, C. and Burstyn-Cohen, T. (2005). Early stages of neural crest ontogeny: Formation and regulation of cell delamination. Int. J. Dev. Biol. 49: 105-116.

Kalcheim, C., Stanke, M., Rohrer, H., Jessen, K., and Mirsky, R. (2006) Novel perspectives in research on the neural crest and its derivatives.. In Cell Signalling and Growth Factors in Development. Eds. K. Unsicker and K. Krieglstein. Wiley-VCH., 12:395-448.

Unsicker, K. Huber, K Schütz, G. and Kalcheim, C. (2005) The chromaffin cell and its development. Neurochemical Res. 30:921-925.

Own project-related publications since the last application (submitted/In preparation)

Groysman, M., Shoval, I. and Kalcheim, C. (2008) A negative modulatory role for Rho and Rho-associated kinase signaling in delamination of neural crest cells. Submitted for Publication.

Krispin, S, Kassem, Y. and Kalcheim, C (2008) A dynamic spatiotemporal  fate map of neural crest derivatives in the dorsal domain of the neural tube . In Preparation.

Huber, K, Franke, A., Brühl, B., Krispin, S., Ernsberger, U., Schober, A., von Bohlen und Halbach, O., Rohrer, H., Kalcheim, C. , and Unsicker, K. (2008) Persistent expression of BMP-4 in embryonic chick adrenal cortical cells and its role in chromaffin cell development. Submitted for publication.

Own project-related publications prior to 2005 (selected publications)

Burstyn-Cohen T. and Kalcheim, C. (2002) Association between the cell cycle and neural crest delamination through regulation of G1-S transition. Dev. Cell. 3:383-395.

Debby-Brafman, A., Burstyn-Cohen, T., Klar, A. and Kalcheim, C. (1999) F-spondin is expressed in somite regions avoided by neural crest cells and mediates the inhibition of distinct somitic domains to neural crest migration. Neuron 22:475-488.

Huber K, Combs S, Ernsberger U, Kalcheim C, Unsicker K (2002). Generation of neuroendocrine chromaffin cells from sympathoadrenal progenitors: beyond the glucocorticoid hypothesis. In: The chromaffin cell: transmitter biosynthesis, storage, release, actions, and informatics“O´Connor, D., Eiden, L., eds.  Ann. NY Acad. Sci., 971:554-559.

Kalcheim, C.  (2000) Mechanisms of early neural crest development: From cell specification to migration. International Rev. Cytol: A survey of Cell Biology 200: 143-195.

Kalcheim C, Langley K, Unsicker K (2002) From the neural crest to chromaffin cells: Introduction to a session on chromaffin cell development. In:"The chromaffin cell: transmitter biosynthesis, storage, release, actions, and informatics“ (O´Connor, D., Eiden, L., eds). Ann. NY Acad. Sci., 971:544-546.

Le Douarin, N.M. and Kalcheim, C. (1999) The Neural Crest. 2cond Edition. Cambridge University Press. New York.

Sela-Donenfeld, D. and Kalcheim, C. (1999) Regulation of the onset of neural crest migration by coordinated activity of BMP4 and noggin in the dorsal neural tube. Development 126: 4749-4762.

Sela-Donenfeld, D. and Kalcheim, C. (2000) Inhibition of noggin expression in the dorsal neural tube by somitogenesis: a mechanism for coordinating the timing of neural crest emigration. Development 127:4845-4854.

Sela-Donenfeld D. and Kalcheim, C. (2002) Localized BMP4-noggin interactions generate the dynamic patterning of noggin expression in somites. Dev. Biol. 246:311-328.

Yaniv, K; Fainsod, A; Kalcheim, C and Yisraeli, J.K. (2003) The RNA binding protein Vg1RBP is required for cell migrations during early neural development.  Development 130:5649-5661.

Selected publications from other projects outside the SFB since 2005

Ben-Yair, R, and Kalcheim, C. (2005). Lineage analysis of the avian dermomyotome reveals the existence of  bipotent progenitors with dermal and mitotic muscle progenitor fates. Development 132: 689-701.

Ben-Yair, R., and Kalcheim, C. (2008) Notch and BMP differentially act on dermomyotome cells to generate endothelium, smooth and striated muscle. J. Cell Biol. 180: 607-618.

Cinnamon, Y., Ben-Yair, R. and Kalcheim, C. (2006). Differential effects of N-cadherin-mediated adhesion of development of myotomal waves. Development 133:1101-1112.

Kahane, N., Ben-Yair, R., and Kalcheim, C. (2007) Medial pioneer fibers pattern the morphogenesis of early myoblasts derived from the lateral somite. Dev. Biol. 305: 439-450.

Kalcheim, C. and Ben-Yair, R. (2005). Cell rearrangements during development of the somite and its derivatives. Curr. Opin. Genet. Dev. 15: 1-10.

Kalcheim, C.,  Kahane, N., Cinnamon, Y. and Ben-Yair, R. (2006) Mechanisms of lineage segregation in the avian dermomyotome. Anat. Embryol. 211, Suppl. 1, S31-36.

Groysman, M., Shoval, I. and Kalcheim, C. (2008) A negative modulatory role for Rho and Rho-associated kinase signaling in delamination of neural crest cells. Submitted for Publication.

Krispin, S, Kassem, Y. and Kalcheim, C (2008) A dynamic spatiotemporal fate map of neural crest derivatives in the dorsal domain of the neural tube . In Preparation.

Huber, K, Franke, A., Brühl, B., Krispin, S., Ernsberger, U., Schober, A., von Bohlen und Halbach, O., Rohrer, H., Kalcheim, C. , and Unsicker, K. (2008) Persistent expression of BMP-4 in embryonic chick adrenal cortical cells and its role in chromaffin cell development. Submitted for publication.

Chaya Kalcheim

Dept. of Medical Neurobiology, IMRIC,

Hebrew University of Jerusalem- Hadassah Medical School

Jerusalem 91120

Israel

Phone: 00972-2-6758438
Fax:     00972-2-6758438
email:   kalcheim(at)nn-shum.cc.huji.ac.il