C. elegansSoxB genes are dispensable for embryonic neurogenesis but required for terminal differentiation of specific neuron types

Abstract

Neurogenesis involves deeply conserved patterning molecules, such as the proneural basic helix-loop-helix transcription factors. Sox proteins and specifically members of the SoxB and SoxC groups are another class of conserved transcription factors with an important role in neuronal fate commitment and differentiation in various species. In this study, we examine the expression of all five Sox genes of the nematode C. elegans and analyze the effect of null mutant alleles of all members of the SoxB and SoxC groups on nervous system development. Surprisingly, we find that, unlike in other systems, neither of the two C. elegans SoxB genes sox-2 (SoxB1) and sox-3 (SoxB2), nor the sole C. elegans SoxC gene sem-2, is broadly expressed throughout the embryonic or adult nervous system and that all three genes are mostly dispensable for embryonic neurogenesis. Instead, sox-2 is required to maintain the developmental potential of blast cells that are generated in the embryo but divide only postembryonically to give rise to differentiated neuronal cell types. Moreover, sox-2 and sox-3 have selective roles in the terminal differentiation of specific neuronal cell types. Our findings suggest that the common themes of SoxB gene function across phylogeny lie in specifying developmental potential and, later on, in selectively controlling terminal differentiation programs of specific neuron types, but not in broadly controlling neurogenesis.

Postmitotic diversification of olfactory neuron types is mediated by differential activities of the HMG‐box transcription factor SOX‐2

“…The function of vertebrate Sox2 protein is currently under intense study in the context of stem cell biology. Together with another recent report (Vidal et al , ), our paper significantly broadens the perspective of Sox2 function by showing that Sox2 can also have a role in terminal neuronal differentiation, through direct regulation of target genes that define the differentiated state of a neuron.…”

“…The expression of sox‐2 in AWC and AWB is maintained throughout life. sox‐2 is also continuously expressed in other sensory neurons (IL1, IL2, URA, URB, OLL), interneurons (AIM, AIN, AVK, RIH), and motor neurons (RME), as well as in other tissues such as head hypodermis, arcade cells, and rectal epithelial cells (Vidal et al , ).…”

A cellular and regulatory map of the GABAergic nervous system ofC. elegans

“…B: Regulatory map of neurotransmitter specification. Data is from this paper for GABA and from following papers for additional neurons: (Alqadah et al, 2015;Altun-Gultekin et al, 2001;Doitsidou et al, 2013;Flames and Hobert, 2009;Kratsios et al, 2015;Kratsios et al, 2011;Pereira et al, 2015;Serrano-Saiz et al, 2013;Sze et al, 2002;Vidal et al, 2015;Zhang et al, 2014) Movie 1: Flyover movies ACh (red), Glu (mint), GABA (blue), monoaminergic (green) neurons. This movie was generated by Chris Grove.…”

Sex-determining region Y-box protein 3 induces epithelial-mesenchymal transition in osteosarcoma cells via transcriptional activation of Snail1

“…Sex-determining region Y-box protein 3 (SOX3) is a member of the Sox family of transcription factors that plays an important role in developmental processes, including neurogenesis [16], testis development [17], and chondrogenesis [18], among others [19, 20]. The expression of SOX3 decreases as development proceeds, and correlates with the cellular switch from proliferation to differentiation [21].…”