Enables RNA polymerase II transcription regulatory region sequence-specific DNA binding activity and RNA polymerase II-specific DNA-binding transcription factor binding activity. Involved in neuron fate specification and positive regulation of transcription by RNA polymerase II. Acts upstream of or within with a positive effect on nematode larval development. Located in nucleus. Expressed in several structures, including IL1 neuron; P3.p male; neuroblasts; rectal epithelial cell; and ventral nerve cord. Human ortholog(s) of this gene implicated in several diseases, including Dandy-Walker syndrome; X-linked VACTERL association; and holoprosencephaly 5. Is an ortholog of several human genes including ZIC1 (Zic family member 1); ZIC2 (Zic family member 2); and ZIC3 (Zic family member 3).