RT Journal Article SR Electronic T1 The conserved ASCL1/MASH-1 ortholog HLH-3 specifies sex-specific ventral cord motor neuron fate in C. elegans JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.06.04.134767 DO 10.1101/2020.06.04.134767 A1 Lillian M. Perez A1 Aixa Alfonso YR 2020 UL http://biorxiv.org/content/early/2020/06/05/2020.06.04.134767.abstract AB Neural specification can be regulated by one or many transcription factors. Here we identify a novel role for one conserved proneural factor, the bHLH protein HLH-3, implicated in the specification of sex-specific ventral cord motor neurons in C. elegans. In the process of characterizing the role of hlh-3 in neural specification, we document that differentiation of the ventral cord type C neurons, VCs, within their motor neuron class, is dynamic in time and space. Expression of VC class-specific and subclass-specific identity genes is distinct through development and dependent on where they are along the A-P axis (and their position in proximity to the vulva). Our characterization of the expression of VC class and VC subclass-specific differentiation markers in the absence of hlh-3 function reveals that VC fate specification, differentiation, and morphology requires hlh-3 function. Finally, we conclude that hlh-3 cell-autonomously specifies VC cell fate.Competing Interest StatementThe authors have declared no competing interest.