Description
Each olfactory sensory neuron (OSN) chooses a single odorant receptor (OR) gene from the class I or class II OR repertoire in mice. We have found that the transcription factor Bcl11b, which is coexpressed with class II OR genes both in frog and mouse, determines the class of OR to be expressed in OSNs. Both loss- and gain-of-function analyses demonstrate that Bcl11b is necessary for class II genes expression, by suppressing the class I-specific enhancer. Overall, we identified a unique transcriptional mechanism that serves as a binary switch for the OR class choice that is likely to have contributed to the acquisition of terrestrial-specific class II OR expression.