Page 46 - Q. Neuroscience

[Q. Neuroscience-28]

Gene regulatory networks underlying cell fate specification

of a C. elegans sensory/inter/motor neuron-type

Woojung Heo¹, Hyeonjeong Hwang¹, Kyuhyung Kim¹

¹Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea

Neuronal differentiation is coordinated through a cascade of gene expression via interactions between trans-acting
transcription factors and cis-regulatory elements of their target genes. However, the mechanisms of how specific
transcription factors determine neuronal cell fate are still not clear. In C. elegans, the IL1 sensory/inter/motor neurons

consist of six neurons that appear to regulate the rate and pattern of foraging movement (Hart et al., 1995). To

identify molecular and cellular mechanisms by which IL1s are terminally differentiated, we searched for cis-regulatory
motifs and trans-acting transcription factors of IL1s. First, we performed promoter analysis of the set of genes that
are specifically expressed in IL1s, including flp-3 neuropeptide gene (Kim et al., 2004). We identified a motif that is

necessary for flp-3 expression in IL1L/R. We also found that a similar motif exists in promoters of other IL1-expressed
genes including unc-8 and eat-4. To investigate trans-acting factor, we performed forward mutagenesis screens and

isolated nfya-1 mutants which show decreased flp-3 expression in IL1L/R. Transient NFYA-1 expression in nfya-1
mutants restores flp-3 expression. We are currently identifying the function of nfya-1 gene in IL1 neuronal

specification.