Wiring the Brain by Clustered Protocadherin Neural Codes
1 Center for Comparative Biomedicine, Ministry of Education Key Lab of Systems Biomedicine, State Key Laboratory of Oncogenes and Related Genes, Joint International Research
Laboratory of Metabolic and Developmental Sciences, Institute of Systems Biomedicine, Xinhua Hospital, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
Abstract
There are more than a thousand trillion specific synaptic connections in the human brain and over a million new specific connections are formed every second during the early years of life. The assembly of these staggeringly complex neuronal circuits requires specific cell-surface molecular tags to endow each neuron with a unique identity code to discriminate self from non-self. The clustered protocadherin (Pcdh) genes, which encode a tremendous diversity of cell-surface assemblies, are candidates for neuronal identity tags. We describe the adaptive evolution, genomic structure, and regulation of expression of the clustered Pcdhs. We specifically focus on the emerging 3-D architectural and biophysical mechanisms that generate an enormous number of diverse cell-surface Pcdhs as neural codes in the brain.
Keywords
Clustered protocadherins; Genome architecture; Neuronal identity; Adhesion specificity; Selfavoidance; Cell recognition
