Morphogenesis of the node and notochord: The cellular basis for the establishment and maintenance of left-right asymmetry in the mouse Journal Article

Authors: Lee, J. D.; Anderson, K. V.
Article Title: Morphogenesis of the node and notochord: The cellular basis for the establishment and maintenance of left-right asymmetry in the mouse
Abstract: Establishment of left-right asymmetry in the mouse embryo depends on leftward laminar fluid flow in the node, which initiates a signaling cascade that is confined to the left side of the embryo. Leftward fluid flow depends on two cellular processes: motility of the cilia that generate the flow and morphogenesis of the node, the structure where the cilia reside. Here, we provide an overview of the current understanding and unresolved questions about the regulation of ciliary motility and node structure. Analysis of mouse mutants has shown that the motile cilia must have a specific structure and length, and that they must point posteriorly to generate the necessary leftward fluid flow. However, the precise structure of the motile cilia is not clear and the mechanisms that position cilia on node cells have not been defined. The mouse node is a teardrop-shaped pit at the distal tip of the early embryo, but the morphogenetic events that create the mature node from cells derived from the primitive streak are only beginning to be characterized. Recent live imaging experiments support earlier scanning electron microscopy (SEM) studies and show that node assembly is a multi-step process in which clusters of node precursors appear on the embryo surface as overlying endoderm cells are removed. We present additional SEM and confocal microscopy studies that help define the transition stages during node morphogenesis. After the initiation of left-sided signaling, the notochordal plate, which is contiguous with the node, generates a barrier at the embryonic midline that restricts the cascade of gene expression to the left side of the embryo. The field is now poised to dissect the genetic and cellular mechanisms that create and organize the specialized cells of the node and midline that are essential for left-right asymmetry. © 2008 Wiley-Liss, Inc.
Keywords: review; nonhuman; mouse; animals; mice; gene expression; confocal microscopy; embryo; embryo development; morphogenesis; cell specificity; gene expression regulation, developmental; embryo, mammalian; gene control; embryonic structures; cell motility; eukaryotic flagellum; body patterning; cilia; developmental stage; zebra fish; endoderm; xenopus; node; primitive streak; phase transition; notochord; scanning electron microscopy; cell ultrastructure; left-right asymmetry; primordium
Journal Title: Developmental Dynamics
Volume: 237
Issue: 12
ISSN: 1058-8388
Publisher: Wiley Periodicals, Inc  
Date Published: 2008-12-01
Start Page: 3464
End Page: 3476
Language: English
DOI: 10.1002/dvdy.21598
PUBMED: 18629866
PROVIDER: scopus
PMCID: PMC2593123
Notes: --- - "Cited By (since 1996): 21" - "Export Date: 17 November 2011" - "CODEN: DEDYE" - "Source: Scopus"
Citation Impact
MSK Authors
  1. Jeffrey D Lee
    8 Lee
  2. Kathryn Anderson
    148 Anderson