A new developmental compartment in the forebrain regulated by Lunatic fringe

Abstract

We identified a compartment in the avian prosencephalon, whose cell-lineage-restricted borders enclose about one-third of the early prosencephalic vesicle, defining a region that later narrows to form the zona limitans intrathalamica (zli). Lunatic fringe (L-fng) is expressed in domains flanking the compartment, delineating its anterior and posterior borders; ectopic L-fng expression is sufficient to direct cells to sort out of the zli, and can also disrupt the borders, preventing zli formation. The lack of similarly oriented fringe borders elsewhere in the prosencephalon indicates that the mechanism for forming the zli compartment differs from that for the proposed segmental subdivisions of the forebrain, prosomeres¹.