AS-C proteins are involved in the determination of the neuronal precursors in the peripheral nervous system and the central nervous system. Efficient DNA binding requires dimerization with another bHLH protein. L(1)SC, SC and AC strongly label the presumptive stomatogastric nervous system, while ASE is more prominent in the presumptive procephalic lobe. AS-C proteins are expressed first earlier in ectoderm and then in the internalized neuroblasts, while T8 is expressed in presumptive neural precursors, once they have segregated from the ectoderm.