Png-1, a nervous system-specific zinc finger gene, identifies regions containing postmitotic neurons during mammalian embryonic development.

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.