11.txt

the test core for find word in xxx.txt

1: Development. 2007 Apr;134(8):1509-18. Epub 2007 Mar 14.

Cell fate polarization in ascidian mesenchyme/muscle precursors by directed FGF
signaling and role for an additional ectodermal FGF antagonizing signal in
notochord/nerve cord precursors.

Kim GJ, Kumano G, Nishida H.

Faculty of Marine Bioscience and Technology, Kangnung National University,
Gangneung Daehangno, Gangneung 210-702, Republic of Korea. [e-mail]

Asymmetric cell division plays a fundamental role in generating various types of 
embryonic cell. In ascidian embryos, asymmetric cell divisions occur in the
vegetal hemisphere in a manner similar to those found in Caenorhabditis elegans. 
Early divisions in embryos of both species involve inductive events on a single
mother cell that result in production of daughters with different cell fates.
Here we show in the ascidian Halocynthia roretzi that polarity of
muscle/mesenchyme mother precursors is determined solely by the direction from
which the FGF9/16/20 signal is presented, a role similar to that of Wnt signaling
in the EMS and T cell divisions in C. elegans. However, polarity of nerve
cord/notochord mother precursors is determined by possible antagonistic action
between the FGF signal and a signal from anterior ectoderm, providing a new
mechanism underlying asymmetric cell division. The ectoderm signal suppresses
MAPK activation and expression of Hr-FoxA, which encodes an intrinsic competence 
factor for notochord induction, in the nerve cord lineage.

PMID: 17360771 [PubMed - indexed for MEDLINE]

Related Links

    HrzicN, a new Zic family gene of ascidians, plays essential roles in the neural
tube and notochord development. [Development. 2002] PMID:12421701

    An FGF signal from endoderm and localized factors in the posterior-vegetal egg
cytoplasm pattern the mesodermal tissues in the ascidian embryo. [Development.
2000] PMID:10851130

    Ephrin-Eph signalling drives the asymmetric division of notochord/neural
precursors in Ciona embryos. [Development. 2007] PMID:17344225

    Maternal macho-1 is an intrinsic factor that makes cell response to the same FGF 
signal differ between mesenchyme and notochord induction in ascidian embryos.
[Development. 2003] PMID:12954719

    An Ets transcription factor, HrEts, is target of FGF signaling and involved in
induction of notochord, mesenchyme, and brain in ascidian embryos. [Dev Biol.
2003] PMID:12941619