...Julia E. VanderMeer; Robin P. Smith; Stacy L. Jones; Nadav Ahituv The limb is widely used as a model developmental system and changes to gene expression patterns in its signaling centers, notably the zone of polarizing activity (ZPA) and the apical ectodermal ridge (AER), are known to cause limb...

...Jesus C. Casanova; Veronica Uribe; Claudio Badia-Careaga; Giovanna Giovinazzo; Miguel Torres; Juan Jose Sanz-Ezquerro The apical ectodermal ridge (AER) is a specialized epithelium located at the distal edge of the limb bud that directs outgrowth along the proximodistal axis. Although the molecular...

...Theo P. Hill; Makoto M. Taketo; Walter Birchmeier; Christine Hartmann Recently canonical Wnt signaling in the ectoderm has been shown to be required for maintenance of the apical ectodermal ridge (AER) and for dorsoventral signaling. Using conditional gain- and loss-of-functionβ-catenin alleles, we...

.... In the limb, this antagonistic action regulates the formation of the apical ectodermal ridge (AER) in both the mesenchyme and the AER itself, and also controls pattern formation along the proximodistal axis of the limb. Our data introduce a new paradigm of BMP antagonism during limb development mediated...

... that cCPZ expression is restricted to epithelial somites, sclerotome,paraxial head mesoderm and the AER of the limb bud. Ectopic expression of cCPZ in the dermomyotome at the wing level has dramatic effects on the expression of Pax1 and Pax3 , and on the morphogenesis of scapula and rostral ribs...

... to be analyzed further. Fgf4 expression was not evident during GT development (data not shown) although it is expressed in posterior AER and is postulated to function in the control of limb mesenchyme proliferation. This may, therefore, represent a different mode of gene expression profile during GT...

.... Evidence suggests that the pattern and maintenance of expression of these genes are dependent on a number of factors including regulatory loops between genes expressed in the AER and those in the underlying mesenchyme. We show here that the mouse mutation dominant hemimelia ( Dh ) alters the pattern...

...Cynthia A. Loomis; Robin A. Kimmel; Chun-Xiang Tong; Jacques Michaud; Alexandra L. Joyner ABSTRACT The apical ectodermal ridge (AER), a rim of thickened ectodermal cells at the interface between the dorsal and ventral domains of the limb bud, is required for limb outgrowth and patterning. We have...

.... Signals from dorsal and ventral ectoderm control dorso-ventral patterning while the apical ectodermal ridge (AER) controls bud outgrowth and patterning along the proximo-distal axis. We show, using cell-fate tracers, the existence of two distinct ectodermal compartments, dorsal versus ventral, in both...

... is only realised when placed adjacent to the AER and appears to be mediated through Shh induction, suggesting that Hoxb-8 may lie genetically upstream of Shh . Accordingly, Hoxb-8 expression is rapidly induced by retinoic acid (RA) treatment in the anterior of the forelimb in a spatial and temporal manner...

... expansion of the apical ectodermal ridge (AER), suggesting that En-1 is also required for proper formation of the AER. To further investigate the role En plays in dorsoventral patterning and AER formation, we have used the replication competent retroviral vector, RCAS, to mis-express mouse En-1 in the early...

... AER apical ectodermal ridge D-V patterning EN1 FGF8 limb development limbless SHH Sonic hedgehog WNT7A Development of the vertebrate limb depends on the establishment and maintenance of discrete signaling centers within the limb bud: the apical ectodermal ridge (here termed...