Differential expression of N‐ and R‐cadherin in functional neuronal systems and other structures of the developing chicken brain

Abstract

Cadherins are a family of cell surface molecules mediating calcium-dependent cell-cell adhesion in a variety of tissues. More than a dozen cadherins are expressed in the vertebrate brain. To obtain insight into the biological significance of this diversity in cadherin expression, we mapped the expression of N- and R-cadherin in the brain of the developing chicken embryo (days 2-19 of incubation) by immunohistochemical and in situ hybridization techniques. Whereas the expression of N- and R-cadherin is relatively uniform or weak in early (about 2-5 days of incubation) and late development (15 days of incubation to hatching stage), these two molecules are differentially expressed in specific nuclei and fiber tracts between days 6-11 of incubation. For example, in the mes- and diencephalon, one of the tectofugal pathways and its target nuclei, here called the tecto-pretecto-rotundal system, express N-cadherin. R-cadherin is expressed by a different tectofugal system, the tectoisthmic pathway. The other tectofugal systems express neither N- nor R-cadherin. In addition, a small number of other mes- and diencephalic nuclei express N- or R-cadherin. On the basis of these results and experimental evidence from other studies, we speculate that the two cadherins are involved in the formation and segregation of particular functional systems within the vertebrate central nervous system (CNS) by regulating the formation of nuclei, and the pathfinding and/or the selective fasciculation of neurites. Apart from neuronal elements, a variety of vascular and ependymal structures also express N-cadherin or R-cadherin, e.g., the parenchymal blood vessels, the choroid plexus, the floor and roof plates, and the ventricular lining. These findings suggest that the two cadherins play a variety of roles during the development of neuronal and nonneuronal epithelial structures throughout CNS development.

Cadherins in development: cell adhesion, sorting, and tissue morphogenesis

“…Although there is no obvious functional correlation between neurons within a particular region and the cadherins expressed in that region, as development proceeds several cadherins become restricted to specific circuits within the CNS (Suzuki et al 1997). In other cases, multiple cadherins are expressed in one brain region that receives information from (Arndt et al 1998;Redies et al 2000) or sends information to several neuronal structures (Redies et al 1993;Wohrn et al 1999), suggesting in this case a role for cadherins in the control of cell-cell networks involved in the transmission of different signals.…”

Hesgenes regulate size, shape and histogenesis of the nervous system by control of the timing of neural stem cell differentiation

“…They initially give rise to neurons and later to other cell types such as ependymal cells and astrocytes. Ependymal cells are the internal lining of the neural tube and carry the adherens junction (Lagunowich et al, 1992;Møllgård et al, 1987;Redies et al, 1993), while astrocytes produce laminin (Liesi et al, 1983). Thus, in the wild type, at later stages when radial glial cells disappear, they are replaced by ependymal cells and astrocytes.…”

The Expression Pattern of the Transcription Factor Phox2 Delineates Synaptic Pathways of the Autonomic Nervous System

“…Precedents for expression of the same adhesion molecule by both axons and their postsynaptic partners can be found in the literature. During chick brain development, for instance, strong expression of the two homophilic adhesion molecules N-and R-cadherin is restricted to two different tectofugal pathways and to the nuclei with which they connect (Redies et al, 1993). Another example is provided by limbic system-associated membrane protein (LAMP), expressed by functionally interconnected cortical and subcortical neurons of the limbic system (Keller et al, 1989;Pimenta et al, 1995).…”