Using a subtraction cloning approach, we have isolated a set of cDNA clones from mouse neural precursor cells whose respective mRNA levels are down-regulated during the development of mouse brain. Single stranded DNA prepared from neuronal precursor cell cDNA library in lambda Zap vector was subtracted with poly (A)⁺ RNA prepared from postnatal and adult mouse brain to obtain several clones which show developmental down-regulation of expression. Their patterns of expression indicate that these genes may play important roles during the embryonic development and differentiation of central nervous system.