Identification of Neural Crest and Glial Enhancers at the Mouse Sox10 Locus through Transgenesis in Zebrafish

Abstract

Sox10 is a dynamically regulated transcription factor gene that is essential for the development of neural crest–derived and oligodendroglial populations. Developmental genes often require multiple regulatory sequences that integrate discrete and overlapping functions to coordinate their expression. To identify Sox10 cis-regulatory elements, we integrated multiple model systems, including cell-based screens and transposon-mediated transgensis in zebrafish, to scrutinize mammalian conserved, noncoding genomic segments at the mouse Sox10 locus. We demonstrate that eight of 11 Sox10 genomic elements direct reporter gene expression in transgenic zebrafish similar to patterns observed in transgenic mice, despite an absence of observable sequence conservation between mice and zebrafish. Multiple segments direct expression in overlapping populations of neural crest derivatives and glial cells, ranging from pan-Sox10 and pan-neural crest regulatory control to the modulation of expression in subpopulations of Sox10-expressing cells, including developing melanocytes and Schwann cells. Several sequences demonstrate overlapping spatial control, yet direct expression in incompletely overlapping developmental intervals. We were able to partially explain neural crest expression patterns by the presence of head to head SoxE family binding sites within two of the elements. Moreover, we were able to use this transcription factor binding site signature to identify the corresponding zebrafish enhancers in the absence of overall sequence homology. We demonstrate the utility of zebrafish transgenesis as a high-fidelity surrogate in the dissection of mammalian gene regulation, especially those with dynamically controlled developmental expression.

Integration of ChIP-seq and machine learning reveals enhancers and a predictive regulatory sequence vocabulary in melanocytes

“…Hereafter we refer to these 2489 loci as ''putative melanocyte enhancers'' (Supplemental Tables S4-S7). These putative melanocyte enhancers include previously reported enhancers at Tyr and Sox10 (Murisier et al 2007;Antonellis et al 2008), as well as novel enhancers at a number of other genes central to melanocyte biology, including Mitf, Tyrp1, Kit, and Mc1r (Supplemental Fig. S2).…”

“…We used an established pipeline for analyzing putative enhancers in zebrafish (Fisher et al 2006a,b;McGaughey et al 2008;Prasad et al 2011), which we have previously used to analyze melanocyte regulatory elements at Sox10 (Antonellis et al 2008) and GPNMB . The 10 putative enhancers tested were chosen at random from the 50 analyzed in vitro as described above.…”

Desert Hedgehog Links Transcription Factor Sox10 to Perineurial Development

“…Similar to the other SoxE proteins Sox8 and Sox9, Sox10 can bind to DNA as monomer or dimer (Wegner, 2010), and it has been shown for at least two Sox10-responsive enhancers that a dimer site cannot simply be replaced by a monomer site without a significant loss in enhancer activity Jagalur et al, 2011). It has even been postulated that dimeric binding is such a crucial feature that it can be used to predict Sox10-dependent neural-crest enhancers (Antonellis et al, 2008). For Schwann-cell-specific enhancers that are activated by Sox10, there seems to be no strict reliance on dimeric binding.…”

Chromatin-remodeling enzymes in control of Schwann cell development, maintenance and plasticity

“…We show that HDAC1/2 and Sox10 interact to activate the promoter of the early lineage marker Myelin protein zero (P0 [25]) and of Pax3, another key transcription factor for SC specification [26,27]. In turn, Pax3 and Sox10 activate the Sox10 MCS4 enhancer (also called U3 [28,29]) to maintain high levels of Sox10, which induces expression of P0 and Fatty acid binding protein 7 (Fabp7), another early peripheral glia marker [30].…”

“…We show that HDAC1/2 and Sox10 interact to activate the promoter of the early lineage marker Myelin protein zero (P0 [25]) and of Pax3, another key transcription factor for SC specification [26,27]. In turn, Pax3 and Sox10 activate the Sox10 MCS4 enhancer (also called U3 [28,29]) to maintain high levels of Sox10, which induces expression of P0 and Fatty acid binding protein 7 (Fabp7), another early peripheral glia marker [30].HDAC1/2 regulate radial sorting, SC survival, induction and maintenance of myelination HDAC1/2 have also essential functions at later developmental stages and in the maintenance of integrity in adult nerves. Ablation of HDAC1/2 in SC precursors (by crossing Hdac1/2 floxed mice with mice expressing Cre under control of the Dhh promoter) leads to radial sorting delay and virtual absence of myelin, followed by massive SC apoptosis [31].…”