Fig. 2. MicroRNAs control differentiation. Neuronal specification of ASEL and ASER cells by lsy-6 microRNA and miR-273. che-1, unc-37 and ceh-36/lin-49 are required for the neuronal determination of the pair of ASE neurons. The ASE cells differ in the asymmetric expression of two candidate chemoreceptor genes, gcy-7 (in ASEL) and gcy-5 (in ASER), which also define different chemosensory functions. The microRNA lsy-6 represses the translation of cog-1 mRNA, which results in the expression of lim-6 and gcy-7 (shown in green). In ASER, miR-273 represses the translation of die-1 mRNA, which leads to the expression of cog-1 and gcy-5 (shown in red). It is still unclear where che-1 acts in this pathway.