Embryonic stem (ES) cells can self-renew maintaining the undifferentiated state. Self renewal requires many factors such as Oct4, Sox2, FoxD3, and Nanog. NF- is a transcription factor involved in many biological activities. Expression and activity of NF- increase upon differentiation of ES cells. Reportedly, Nanog protein directly binds to NF- protein and inhibits its activity in ES cells. Here, we found a potential binding site of NF- in the human Nanog promoter and postulated that NF- protein may regulate expression of the Nanog gene. We used human embryonic carcinoma (EC) cells as a model system of ES cells and confirmed decrease of Nanog and increase of NF- upon differentiation induced by retinoic acid. Although deletion analysis on the DNA fragment including NF- binding site suggested involvement of NF- in the negative regulation of the promoter, site-directed mutation of NF- binding site had no effect on the Nanog promoter activity. Furthermore, no direct association of NF- with the Nanog promoter was detected during differentiation. Therefore, we conclude that NF- protein may not be involved in transcriptional regulation of Nanog gene expression in EC cells and possibly in ES cells.

배아 줄기세포는 미분화상태에서 자가 재생을 유지할 수 있다. 자가 재생은 OCT4, SOX2와 NANOG와 같은 많은 인자들이 작용한다. 생쥐 배아 줄기세포에서 OCT4와 SOX2가 Nanog 프로모터에 결합하여 Nanog 유전자의 발현을 촉진한다는 사실은 생쥐 promoter에 관한 정밀분석으로 알려져 있다. 본 연구에서는 인간 Nanog promoter를 정밀 분석하기 위해 연속적인 결손 돌연변이를 가진 promoter-reporter constru