Modulation of sensory information processing by a neuroglobin in .

Sensory receptor neurons match their dynamic range to ecologically relevant stimulus intensities. How this tuning is achieved is poorly understood in most receptors. The roundworm avoids 21% O and hypoxia and prefers intermediate O concentrations. We show how this O preference is sculpted by the antagonistic action of a neuroglobin and an O-binding soluble guanylate cyclase. These putative molecular O sensors confer a sigmoidal O response curve in the URX neurons that has highest slope between 15 and 19% O and approaches saturation when O reaches 21%. In the absence of the neuroglobin, the response curve is shifted to lower O values and approaches saturation at 14% O In behavioral terms, neuroglobin signaling broadens the O preference of while maintaining avoidance of 21% O A computational model of aerotaxis suggests the relationship between GLB-5-modulated URX responses and reversal behavior is sufficient to broaden O preference. In summary, we show that a neuroglobin can shift neural information coding leading to altered behavior. Antagonistically acting molecular sensors may represent a common mechanism to sharpen tuning of sensory neurons.