Identification of a novel retinoic acid-responsive element within the lamin A/C promoter

A-type lamins are not present in either early embryos or the embryonal carc inoma (EC) cell line. P19 cells, which are EC cell line, are able to expres s A-type lamins upon retinoic acid (RA) treatment. Here we report that a no vel RA-responsive element, termed lamin A/C-RA-responsive element (L-RARE), is located within the lamin A/C promoter. RA activated the luciferase acti vity of the reporter which had four tandem repeats of the wild-type L-RARE, while a loss of function mutant, which altered CACCCCC to CACtatC within L -RARE, did not respond. Four specific binding complexes of L-RARE, Complexe s-A, -B, -C, and -D, were detected in protein extracts obtained from P19 ce lls treated with and without RA. Specific antibodies revealed that Sp1 and Sp3 were included in Complex-A and Complexes-B and -C, respectively. Thus, L-RARE was important in the RA-mediated activation of the lamin A/C promote r and was recognized by DNA binding proteins. (C) 2000 Academic Press.