Search results
Results from the WOW.Com Content Network
In higher animals including humans, retinoic acid regulates differential expression of Hox genes along the anteroposterior axis. [36] Genes in the 3' ends of Hox clusters are induced by retinoic acid resulting in expression domains that extend more anteriorly in the body compared to 5' Hox genes that are not induced by retinoic acid resulting ...
Signals that control anteroposterior neural development include FGF and retinoic acid, which act in the hindbrain and spinal cord. [16] The hindbrain, for example, is patterned by Hox genes , which are expressed in overlapping domains along the anteroposterior axis under the control of retinoic acid.
Limb mesenchymal cells, when dissociated and grown in culture or reintroduced within ectodermal "hulls" can recapitulate essential aspects of pattern formation, morphogenesis and differentiation. [36] [37] Peculiarities of the limb skeletal pattern in the mouse Doublefoot mutant are predicted outcomes of a Turing-type mechanism. [38]
The pattern of Hox gene expression can be divided up into three phases throughout limb bud development, which corresponds to three key boundaries in proximal-distal limb development. The transition from the first phase to the second phase is marked by the introduction of Shh signals from the ZPA . [ 19 ]
Patterning along the limb bud requires signals from many sources. Specifically, proteins called transcription factors (TF) help control the rate at which a gene is transcribed. The limb bud expresses a TF called ALX4 at the anterior part of the mesoderm, with the TF HOXB8 being expressed at the posterior portion. The Alx4 region, the medial ...
In human and non-human anatomy, three principal planes are used: The sagittal plane or lateral plane ( longitudinal, anteroposterior ) is a plane parallel to the sagittal suture . It divides the body into left and right.
The discovery of the homeobox in Drosophila flies and its conservation in other animals has led to advancements in understanding the anterior/posterior patterning. Most of the Hox genes in mammals show an expression pattern that parallels the homeotic genes in flies. In mammals, there are four copies of the Hox genes.
Wnt signaling is implicated in the formation of the anteroposterior and dorsoventral (DV) axes. Wnt signaling activity in anterior-posterior development can be seen in mammals, fish and frogs. In mammals, the primitive streak and other surrounding tissues produce the morphogenic compounds Wnts, BMPs , FGFs , Nodal and retinoic acid to establish ...