Transcription regulator (PubMed:17170704, PubMed:27487365). Binds specifically to the MEF2 element, 5'-[TC]TA[AT][AT][AT][AT]TA[AG]-3' in the regulatory elements of target genes, such as chemoreceptors str-1 and srh-234 (PubMed:10882527, PubMed:17170704, PubMed:27487365). Involved in transduction of sensory signals, together with egl-4, kin-29 and hda-4; binding to histone deacetylase hda-4 enables negative modulation of chemoreceptor gene expression in chemosensory neurons (PubMed:17170704, PubMed:18832350). In response to starvation, negatively modulates expression of chemoreceptor srh-234 in ADL sensory neurons, acting in concert with basic helix-loop-helix (bHLH) transcription factors (PubMed:27487365). Plays a role in regulating muscle sensitivity to acetylcholine (ACh) and the magnitude of presynaptic ACh release via a retrograde signal, perhaps by indirectly decreasing Ras-related protein Rab-3 activity (PubMed:18510933). Interacts with histone deacetylase hda-4 isoform b. Expressed broadly throughout most of development. Down-regulated by microRNA mir-1 (PubMed:18510933). Up-regulated in many head neurons during prolonged starvation (PubMed:27487365). Belongs to the MEF2 family.