... p and A are phosphoric and adenosine residues, respectively, and a and n are small integers (a =1, 2, or 3 and n commonly = 2, 3, or 4). Potent inhibitors of proteinbiosynthesis in vivo and ... and combinatorial activity of three classes of gene, denoted A,B, and C, which encode transcription factors. Class A determinesthe fate of whorls 1 and 2 (sepals and petals, respectively) and ... class B determines whorls 2 and 3 (petals and stamens, respectively) and requires the PISTILLATA(PI) and APETALA3 (AP3) genes; class C determines whorl 4(carpels) and requires the AGAMOUS gene...