Zpa

Some articles on zpa:

Diplopodia - Causes
... The zone of polarizing activity (ZPA) in the proximal posterior mesoderm of a tetrapod limb bud is responsible for maintaining the anterior-posterior axis of the growing limb ... The ZPA secretes shh protein, which induces formation of the distal segment of the limb, or autopod, with its posterior side facing the ZPA ... When ZPA cells, non-ZPA cells made to express shh, or simply shh protein-soaked beads are implanted in the anterior side of a limb bud, the end of the resulting limb is duplicated, as in diplopodia ...
Limb Bud - Relevant Experiments
... cells results in the formation a limb bud, AER, ZPA and, subsequently, an entire limb ... with Shh Secretion HOXD11 is expressed most posteriorly, near the ZPA, where the highest levels of Shh expression occur ... When retinoic acid is applied to induce Shh expression, a ZPA is transplanted, or ectopic expression of Shh is stimulated, HOXD11 expression follows ...
Apical Ectodermal Ridge - Relationship Between Hox Gene Expression and Limb Patterning
... regulation of limb development even after the AER and ZPA have been established ... Complex communication ensues as AER-secreted FGFs and ZPA-secreted Shh initiate and regulate Hox gene expression in the developing limb bud ... phase is marked by the introduction of Shh from the ZPA ...
Limb Development - Axial Patterning and Related Issues - Anterior/posterior Patterning
... The Zone of Polarizing Activity (ZPA) in the limb bud has pattern-organizing activity by action of a morphogen gradient of Sonic hedgehog (Shh) ... Shh is both sufficient and necessary to create the ZPA and specify the anterior/posterior pattern in the distal limb (Shh is not necessary for the polarity of the stylopod) ... Shh is maintained in the posterior though a feedback loop between the ZPA and the AER ...