ACTIVATION OF THE GENE FOR TYPE-B NATRIURETIC FACTOR IN MOUSE STEM-CELL CULTURES INDUCED FOR CARDIAC MYOGENESIS

We assessed the temporal transcriptional activity profiles of the gene s for type-B natriuretic factor, BNF, the isoform ANF, and other cardi ac muscle proteins in differentiating cultures derived from multipoten tial mouse cell lines. P19 embryonal carcinoma cells and D3 embryonic stem cells were induced for in vitro cardiac myogenesis; RNA was isola ted at regular intervals throughout the differentiation programs, and mRNAs were detected by reverse transcriptase mediated polymerase chain reactions. The transcriptional activation profiles of the ANF and BNF gene were similar, but there were quantitative differences that were best assayed by use of competitive internal DNA standards. The levels of induced BNF transcripts were highest in the P19 developmental syste m reaching approximately 10 % of adult mouse ventricular muscle levels ; those for ANF were lower, but also readily detected. The cell lines may be used to define the regulatory control elements for natriuretic factor gene expression, in stably transfected cell lines, during cardi ac muscle growth. (C) 1994 Academic Press, Inc.