NeuN is a RNA-binding protein that modulates alternative splicing and is localized both to the nucleus and cytoplasm. It is a member of the RNA-binding FOX (RBFOX) family of splicing regulators which includes RBFOX1 (Fox-1/A2BP1) and RBFOX2 (Fox-2/RBM9). Each FOX family member is differentially expressed – RBFOX1 in neurons, heart, and muscle while RBFOX3 is exclusively limited to neurons.
