|
|
|
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
First published online 7 March 2007
doi: 10.1242/dev.003939
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Developmental Biology Unit, Université Pierre et Marie Curie (Paris VI) and CNRS, Observatoire Océanologique, 06230 Villefranche sur mer, France.
* Author for correspondence (e-mail: yasuo{at}obs-vlfr.fr)
Accepted 14 February 2007
Asymmetric cell divisions produce two sibling cells with distinct fates, providing an important means of generating cell diversity in developing embryos. Many examples of such cell divisions have been described, but so far only a limited number of the underlying mechanisms have been elucidated. Here, we have uncovered a novel mechanism controlling an asymmetric cell division in the ascidian embryo. This division produces one notochord and one neural precursor. Differential activation of extracellular-signal-regulated kinase (ERK) between the sibling cells determines their distinct fates, with ERK activation promoting notochord fate. We first demonstrate that the segregation of notochord and neural fates is an autonomous property of the mother cell and that the mother cell acquires this functional polarity via interactions with neighbouring ectoderm precursors. We show that these cellular interactions are mediated by the ephrin-Eph signalling system, previously implicated in controlling cell movement and adhesion. Disruption of contacts with the signalling cells or inhibition of the ephrin-Eph signal results in the symmetric division of the mother cell, generating two notochord precursors. Finally, we demonstrate that the ephrin-Eph signal acts via attenuation of ERK activation in the neural-fated daughter cell. We propose a model whereby directional ephrin-Eph signals functionally polarise the notochord/neural mother cell, leading to asymmetric modulation of the FGF-Ras-ERK pathway between the daughter cells and, thus, to their differential fate specification.
Key words: ephrin-Eph, ERK, Asymmetric cell division, Ciona, Notochord, Neural
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati 
Twitter What's this?
Related articles in Development:
This article has been cited by other articles:
|
|
 |
|
  A. Kubo, K. S. Imai, and Y. Satou Gene-regulatory networks in the Ciona embryos Brief Funct Genomic Proteomic, June 17, 2009; (2009) elp018v1. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Poliakov, M. L. Cotrina, A. Pasini, and D. G. Wilkinson Regulation of EphB2 activation and cell repulsion by feedback control of the MAPK pathway J. Cell Biol., December 1, 2008; 183(5): 933 - 947. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Qiu, X. Wang, A. Davy, C. Wu, K. Murai, H. Zhang, J. G. Flanagan, P. Soriano, and Q. Lu Regulation of neural progenitor cell state by ephrin-B J. Cell Biol., October 21, 2008; 181(6): 973 - 983. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. Shi and M. Levine Ephrin signaling establishes asymmetric cell fates in an endomesoderm lineage of the Ciona embryo Development, March 1, 2008; 135(5): 931 - 940. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Arvanitis and A. Davy Eph/ephrin signaling: networks Genes & Dev., February 15, 2008; 22(4): 416 - 429. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Hudson, S. Lotito, and H. Yasuo Sequential and combinatorial inputs from Nodal, Delta2/Notch and FGF/MEK/ERK signalling pathways establish a grid-like organisation of distinct cell identities in the ascidian neural plate Development, October 1, 2007; 134(19): 3527 - 3537. [Abstract] [Full Text] [PDF]
|
|
