Expression of doublecortin correlates with neuronal migration and pattern formation in diverse regions of the developing chick brain

The development of functional layers in the brain involves spatially and te mporally regulated gene expression. Through cDNA library screening, we have identified genes that are expressed in a neural-specific manner during bra in development. Sequencing and expression data indicate that one of the clo nes, 18C15, is the chick homologue of doublecortin, a human X-linked gene f ound to be mutated in subcortical laminar heterotopia (double cortex syndro me) and lissencephaly, The 18C15 mRNA contains multiple motifs that are kno wn to regulate mRNA stability in response to inductive signals, and these m otifs are conserved between the chick and human sequences. Doublecortin is found to be expressed at peak levels during early development of the cerebe llum and forebrain, and is expressed in other regions including the tectum, spinal cord, and dorsal root ganglia, This study demonstrates both spatial and temporal regulation of doublecortin expression in the chick, which is associated with early events in brain development, including neuronal migra tion. (C) 1999 Wiley-Liss, Inc.