Although transcribing factors have various roles in cell differentiation, they are particularly critical in regulating relatively simple developmental processes, such as determining which genes get transcribed and which do not. This is often dictated by specific sequence elements within the genes themselves, serving to differentiate and differentiate cell fates and tissues during complex developmental processes. While this mechanism is well understood, there are specific and elegant tools available to target specific transcription factors and to manipulate biological processes with precision and certainty.