Class 1 systems require multiple Cas proteins to come together in a complex to mediate interference against foreign genetic elements making gene editing applications of class 1 systems limited. Class 1 systems are further divided into three CRISPR/Cas types based on the presence of a specific signature protein: Type I contains Cas3, Type III contains Cas10, and the Type IV contains Csf1, a Cas8-like protein. Please see Table for key differences and similarities between the different Class I CRISPR/Cas systems.