Structure and cis‐regulatory analysis of a Drosophila grainyhead neuroblast enhancer

Abstract

Evolutionary analysis of cis-regulatory DNA reveals that enhancers consist of clusters of conserved sequence blocks (CSBs) that are made up of both unique and repeated sequence elements. This study seeks to address the basis for spatial and temporal regulation of neuroblas. A search for temporally restricted CNS NB enhancers identified one within the transcription factor grainyhead (grh) gene locus. The intronic enhancer, grh-15, contains two separable semi-autonomous activities, one that drives expression predominantly within the developing brain NBs and another in ventral cord NBs. To gain insight into the function of the CSBs constituting the brain-specific enhancer, we have systematically deleted each CSB and compared the activity of the altered enhancer to that of the full brain-specific enhancer. While our results indicate that information regulating enhancer activity is highly redundant, we have found that individual CSBs convey expression in subsets of larval lineages that are generated from either Type I or Type II NBs. These studies also highlight how evolutionary sequence conservation can be used as a guide the functional analysis of cis-regulatory DNA.

CORLExpression in theDrosophilaCentral Nervous System Is Regulated by Stage Specific Interactions of Intertwined Activators and Repressors

“…Further, Octamer sites are often found with clustered bHLH and Hox sites where they overlap the Hox core motif. One example of Octamer/Hox overlap in a CNS specific regulatory module is the grainyhead neuroblast enhancer ( Kuzin et al 2018 ). This pattern is also seen in CRM#3 where one of the Octamer sites overlaps the already overlapping EcR and Hox motifs.…”