REPRESSION OF P53-DEPENDENT SEQUENCE-SPECIFIC TRANSACTIVATION BY MEF2C

Lambda ZAP cDNA library constructed from spleen of a p53-deficient mou se was screened by South-Western technique using Fragment A, a DNA iso lated was identical to MEF2c, a MADS-family transcription factor. Tran scripts of the mef2c gene was also detected in spleen where the expres sion has not been reported so far. Isolated clones except clone 2 had a growth-suppression activity on p53-deficient osteosarcoma cell line (Saos II). Clone 2 repressed the transactivation from Fragment A by p5 3, suggesting that MEF2c may act as a negative regulator of p53-respon sive element. (C) 1955 Academic Press, Inc.