Transcription regulator required for seed dispersal. Involved in the differentiation of all three cell types required for fruit dehiscence. Acts as the key regulator in a network including SHP and ALC that controls specification of the valve margin. Works with ALC, SHP, and FUL to allow differentiation of the lignified valve layer, the spring-loaded mechanism of fruit that promotes opening. Regulates the expression of the YJ80 marker. Homodimer (Probable). Heterodimer; possibly with ALC. After fertilization, it is expressed in stripes about four cells wide at the margins of developing wild-type fruit. Also expressed in the inner valve layer, which becomes lignified later in fruit development. Detected in roots. By FUL, which restrict its expression to the margins.