Figure 4From: Parallel evolution of conserved non-coding elements that target a common set of developmental regulatory genes from worms to humansCNEs identify previously characterized enhancer sequences and when located in introns are associated with alternative transcriptional start sites. Five wCNEs are contained within four elements that regulate ser-2, the C. elegans ortholog of human serotonin receptor 1A. The products of ser-2 were identified as components of the AIY interneuron gene battery in C. elegans [60]. ser-2 has at least three alternative transcription start sites that produce a number of different gene products, considered to be expressed in different but overlapping regions [61]. Remarkably, each of the alternative transcription start sites is marked by a wCNE in the proximal upstream region, with additional wCNEs lying further away, highlighting the underlying cis-regulatory elements. The upstream sequences of each of the alternative transcription start sites were defined by deletion analysis [61]. One of the wCNEs lies within an approximately 280 bp element driving expression in the AIY and SIA neuronal cellular subtypes. A second wCNE lies within an approximately 520 bp element driving expression in the RME neurons and also, consistently, in other unidentified neurons. A third wCNE lies within an approximately 1,150 bp element driving expression in the head muscles. Two more wCNEs are contained within a region driving expression in PVD and lateral OLL neurons. Only the experimentally tested constructs that overlap wCNEs are shown in this diagram.Back to article page