Multiple Elements RegulateMash1Expression in the Developing CNS

AbstractMash1, a transcription factor of the basic helix–loop–helix class, is expressed during embryogenesis in restricted regions of the nervous system. An essential role for Mash1 in neural development was demonstrated previously in mice carrying a targeted disruption of theMash1gene. Regulation of the precise temporal and spatial expression ofMash1is thus likely to be important for proper neural development. In this study, sequences that regulateMash1expression in the central nervous system were characterized by assaying the expression oflacZreporter genes in transgenic embryos. A 1158-bp enhancer localized ∼7 kb upstream of theMash1coding region was identified. Deletions within this enhancer region reveal the presence of both positive and negativecis-acting elements. Analysis of multiple sequences within the enhancer demonstrate that different elements preferentially function in different regions within theMash1-specific CNS expression domain. In addition, a role for sequences 3′ of theMash1coding region is revealed, providing evidence for posttranscriptional control ofMash1expression in multiple CNS domains