When A (E-PIF6), B (PhyB-VP16), C (Gal4-KDronpa) and D (NDronpa-VP16) are pro- duced, they interact with the operator binding sites OBD1 (in gE, gF and gG) and OBD2 (in gH, gI and gJ). Thus, proteins produced in previous levels, regulate the expression of the following ones. Light induced transcription, is due to the activacion of proteins B and D, whose structures change according to a certain light wavelenght. Theoretically, only if B* (activated) binds A (which is already attached to the genes), proteins E, F and G will be produced. On the other hand, it occurs similarly with D*, C and proteins H, I and J. The symbol ”+”, makes reference to those genes which can be transcripted because recombinases have not bind to them.