RRC ID 4860
Author Imai KS, Stolfi A, Levine M, Satou Y.
Title Gene regulatory networks underlying the compartmentalization of the Ciona central nervous system.
Journal Development
Abstract The tripartite organization of the central nervous system (CNS) may be an ancient character of the bilaterians. However, the elaboration of the more complex vertebrate brain depends on the midbrain-hindbrain boundary (MHB) organizer, which is absent in invertebrates such as Drosophila. The Fgf8 signaling molecule expressed in the MHB organizer plays a key role in delineating separate mesencephalon and metencephalon compartments in the vertebrate CNS. Here, we present evidence that an Fgf8 ortholog establishes sequential patterns of regulatory gene expression in the developing posterior sensory vesicle, and the interleaved ;neck' region located between the sensory vesicle and visceral ganglion of the simple chordate Ciona intestinalis. The detailed characterization of gene networks in the developing CNS led to new insights into the mechanisms by which Fgf8/17/18 patterns the chordate brain. The precise positioning of this Fgf signaling activity depends on an unusual AND/OR network motif that regulates Snail, which encodes a threshold repressor of Fgf8 expression. Nodal is sufficient to activate low levels of the Snail repressor within the neural plate, while the combination of Nodal and Neurogenin produces high levels of Snail in neighboring domains of the CNS. The loss of Fgf8 patterning activity results in the transformation of hindbrain structures into an expanded mesencephalon in both ascidians and vertebrates, suggesting that the primitive MHB-like activity predates the vertebrate CNS.
Volume 136(2)
Pages 285-93
Published 2009-1
DOI 10.1242/dev.026419
PII dev.026419
PMID 19088089
MeSH Animals Body Patterning / genetics Central Nervous System / embryology* Central Nervous System / metabolism Ciona intestinalis / embryology* Ciona intestinalis / genetics* Ciona intestinalis / metabolism Fibroblast Growth Factors / genetics Gene Expression Profiling Gene Regulatory Networks* Genes, Homeobox Genes, Regulator Signal Transduction Species Specificity Tretinoin / metabolism Vertebrates / embryology Vertebrates / genetics
IF 5.763
Times Cited 74
C.intestinalis / (O.japonicus) Wild C.int