Computational and Experimental Approach for the Identification of Mesencephalon-Specific Cis- Element of Dbx1 Gene - Abstract
Gene regulation is central to the biological processes of differentiation, morphogenesis, and the creation of diversity of cell types. The identification of gene regulatory elements is thus essential for the understanding of the molecular mechanism underlying these processes. Here, we present an integrative approach for the identification and characterization of a cis-element of Dbx1 gene. Dbx1 (developing brain homeobox 1) plays an essential role during development of the central nervous system (CNS). Dbx1 expression is regionally restricted within the brain and spinal cord to define neuronal specific domains. Although the functional roles of Dbx1 have been established, the molecular mechanism that governs Dbx1 regional specific expression is not well understood. Using comparative genomics method, we revealed a highly evolutionarily conserved noncoding DNA fragment of 624 bp
located approximately18 kb upstream of Dbx1 locus (CR5) and is predicted as a cis-element. Using experimental approaches, we show that this cis-element CR5 directs
mesencephalon-specific gene expression during chick embryonic CNS development. Cells with CR5 activity contain a heterogeneous neuronal population suggesting that
CR5 is involved in multiple neuronal lineage development. Together, these findings provide additional insight into the complex regulation of Dbx1 expression during CNS development. In addition, our study established an effective approach for the discovery and characterization of genomic regulatory elements.