Nkx2.2AS is an endogenous antisense transcript to Nkx2.2 gene, subcellularly located in the cytoplasm. We tested if Nkx2.2AS transcripts have any biological function by regulating transcription level of Nkx2.2 coding gene in the differentiation of neural stem cells. Forced expression of Nkx2.2AS in neural stem cells enhanced induction of differentiation along lineage of oligodendrocytes. Further analyses showed that overexpression of Nkx2.2AS induced modest increase in Nkx2.2 mRNA level, suggesting that the upregulation of Nkx2.2 mRNA level can be a minor cause of enhanced induction of oligodendrocytic differentiation by Nkx2.2AS overexpression. These results together imply that Nkx2.2AS has a certain biological function which is likely to be not only based on the affect on transcription level of Nkx2.2 coding but also on the other mechanisms. gene in cis, but also on the other mechanisms. (c) 2008 Elsevier Inc. All rights reserved.