RESUMEN
Cadherins are superfamily of Ca2+-dependent transmembrane glycoproteins with more than 100 members. They play a role in a wide variety of developmental mechanisms, including cell proliferation, cell differentiation, cell-cell recognition, neurite outgrowth and synaptogenesis. We cloned 16 novel members of the classic cadherin and delta-protocadherin subgroups from ferret brain. Their expression patterns were investigated by in situ hybridization in the developing primary visual cortex (V1) of the ferret. Fifteen out of the 16 cadherins are expressed in a spatiotemporally restricted fashion throughout development. Each layer of V1 can be characterized by the combinatorial expression of a subset of cadherins at any given developmental stage. A few cadherins are expressed by subsets of neurons in specific layers or by neurons dispersed throughout all cortical layers. Generally, the expression of protocadherins is more widespread, whereas that of classic cadherins is more restricted to specific layers. At the V1/V2 boundary, changes in layer-specific cadherin expression are observed. In conclusion, our results suggest that cadherins provide a code of potentially adhesive cues for layer formation in ferret V1. The persistence of expression in the adult suggests a functional role also in the mature cortex.
Asunto(s)
Cadherinas/biosíntesis , Corteza Visual/crecimiento & desarrollo , Animales , Mapeo Encefálico , Cadherinas/genética , Clonación Molecular , Cartilla de ADN , ADN Complementario/biosíntesis , ADN Complementario/genética , Femenino , Hurones , Fluoresceína-5-Isotiocianato/análogos & derivados , Hibridación in Situ , Hibridación Fluorescente in Situ , Embarazo , ARN/biosíntesis , ARN/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Tiramina/análogos & derivadosRESUMEN
The expression of 12 different classic cadherins and delta-protocadherins was mapped in consecutive series of sections through the basal ganglia of the postnatal and adult mouse by in situ hybridization. A particular focus was the caudoputamen, which consists of patches (striosomes) and a surrounding matrix that is histologically uniform. The different areas within the caudoputamen are connected specifically to other parts of the basal ganglia and to other brain regions, for example, the substantia nigra. The molecules regulating the morphogenesis and functional connectivity of the basal ganglia are largely unknown. Previous studies suggested that cadherins, a large family of adhesion molecules, are involved in basal ganglia development. In the present work, we study the expression of 12 cadherins and show that the patch and matrix compartments of the caudoputamen express the cadherins differentially, although partial overlap is observed. Moreover, the cadherins are expressed in multiple and diverse gradients within the caudoputamen and other parts of the basal ganglia. The persistence of the expression patterns in the adult basal ganglia suggests the possibility that cadherins also play a role at adult stages. Our results suggest that cadherins provide a code of potentially adhesive cues that specify not only patch and matrix compartments but also multiple molecular gradients within the basal ganglia. This code may relate to patterns of connectivity.