Regulation of the Protocadherin Celsr3 Gene and Its Role in Globus Pallidus Development and Connectivity

The globus pallidus (GP) is a central component of basal ganglia whose malfunctions cause a variety of neuropsychiatric disorders as well as cognitive impairments in neurodegenerative diseases such as Parkinson's disease. Here we report that the protocadherin geneCelsr3 is regulated by the insulator CCCTC -bindingf actor (CTCF) and the repressorn euron-r estrictives ilencerf actor (NRSF, also known as REST) and is required for the development and connectivity of GP. Specifically, CTCF/cohesin and NRSF inhibit the expression ofCelsr3 through specific binding to its promoter. In addition, we found that theCelsr3 promoter interacts with CTCF/cohesin-occupied neighboring promoters. InCelsr3 knockout mice, we found that the ventral GP is occupied by aberrant calbindin-positive cholinergic neurons ectopic from the nucleus basalis of Meynert. Furthermore, the guidepost cells for thalamocortical axonal development are missing in the caudal GP. Finally, axonal connections of GP with striatum, subthalamic nucleus, substantia nigra, and raphe are compromised. These data reveal the essential role ofCelsr3 in GP development in the basal forebrain and shed light on the mechanisms of the axonal defects caused by theCelsr3 deletion.