... [8–12]; (b) the use of anextrinsic promoter (P1) and an alternative, intrinsicpromoter (P2) in the 5¢-end (leading to the formation of TA and DM classes of isoforms, respectively) [13]; and (c) ... opposing roles, mainly the apoptotic TAisoform(s) and the antiapoptotic DM isoforms. In gen-eral, TAp73 isoforms regulate the transcription of DMp73 isoforms, which, in turn, act as dominant ... that the binding of endogenous Sp1 to region A in the fibroblast cellline IMR90 was almost equal to that in the normalHNBE cells (Fig. 2C, lanes 1 and 2). A markedincrease in the level of region...