AvicGFPhb.HG4-1-RNA is detected in neuroblasts at embryonic stages 9 and 10. At embryonic stage 11 labeling is seen in ganglion mother cells. AvicGFPhb.HG4-1-protein is detected in earlier born neuroblasts of the ventral nerve cord at embryonic stage 11. At embryonic stage 16 both AvicGFPhb.HG4-1-RNA and -protein label early-born neurons in the deepest layers of the embryonic CNS.