To identify genes associated with early postmitotic cortical neurons, gene fragments were examined for expression in postmitotic, but not proliferative, zones of the embryonic murine cortex. Through this approach, a novel member of the zinc finger gene family, containing 6 C2HC fingers, was isolated and named postmitotic neural gene-1, or png-1. Embryonic png-1 expression was: 1) nervous system-specific; 2) restricted to zones containing postmitotic neurons; and 3) detected in all developing neural structures examined. In the cortex, png-1 expression was first observed on embryonic day 11, correlating temporally and spatially with the known generation of the first cortical neurons. Gradients of png-1 expression throughout the embryonic central nervous system further correlated temporally and spatially with known gradients of neuron production. With development, expression remained restricted to postmitotic zones, including those containing newly-postmitotic neurons. Png-1 was also detected within two days of neural retinoic acid induction in P19 cells, and expression increased with further neuronal differentiation. These data implicate png-1 as one of the earliest molecular markers for postmitotic neuronal regions and suggest a function as a panneural transcription factor associated with neuronal differentiation.