The developing avian peripheral nervous system has served as an excellent model system for many years for studies of the basic cellular interactions that underlie motor axon pathfinding.
The developing avian lung is formed mainly by branching morphogenesis, but there is also a unique cystic structure, the air sac, in the ventral region.
TH signaling components, consisting of the thyroid hormone receptors (TRs), TRα and TRβ, as well as the deiodinases, Dio2 and Dio3, are expressed in unique spatial and temporal patterns in the developing avian retina [41].
The expression patterns of these important corneous proteins have not been thoroughly studied in developing avian skin appendages.
Previous studies showed that Notch family members were expressed in early mesenchymal cell condensations of murine limb rudiments as well as in developing avian cartilage [ 9, 41].
While STC2 is expressed in developing avian striated muscle and joints [ 49], the physiological roles of STC2 in cattle are unknown.
We have previously demonstrated that spatiotemporal expression of lncRNAs can be conserved in developing avian, marsupial, and eutherian brains (Chodroff et al. 2010).
The origin of this neural activity was first found to be in the cochlea as tetrodotoxin applied to the round window membrane of the developing avian cochlea resulted in the elimination of neural activity throughout the developing auditory system [ 36].
In developing avian muscle and also tissue culture, PKC seemed to be negatively regulated by nerve-evoked activity, thus PKC activity was decreased by innervation and increased by blocking neuromuscular transmission in slow muscles.
However, as shown by the lead concentration in the foetal liver consistent with levels causing mortality in birds [ 1], it can pose a threat for the developing avian egg.
