Fig. 8.

Model of Six1a’s dual and opposing roles in the sensory and neuronal lineages of the developing zebrafish inner ear. In the sensory lineage, Six1a is able to interact with an Eya-like factor. They subsequently recruit an activator complex, leading to the transcriptional activation of Six1a targets, which, in turn, increases cell proliferation while decreasing programmed cell death. The result is the promotion of hair cell formation in the developing otocyst. Conversely, in the neuronal lineage, Six1a is able to interact with a Gro-like factor. They then recruit a repressor complex, leading to the transcriptional repression of Six1a targets, inhibiting cell proliferation and activating programmed cell death, resulting in an inhibition of neuron formation in the developing inner ear. Both roles require Six1a binding to DNA.