Question

Place the following events in the order they occur by listing their assigned letters in that order. A. Cas9 REC domains binds to the guideRNA B. Cas9 complex binds to dsDNA C. Cas9 complex scans dsDNA for PAM sequence D. Cas9 unwinds dsDNA E. The programmable part of the guideRNA binds to its complementary sequence F. Cas9 cuts both strands to generate a double strand break

Answer 1

Answer:  a, b, d, c, e, f

Explanation: The steps of Cas9 DNA recognition and cleavage goes in the following order lettered A, B, D, C, E and F. Cas9 recognizes and binds the sgRNA after which it binds to the double stranded DNA. It then unwinds and scans the dsDNA for its protospacer adjacent motif sequence (PAM) and on recognition the sgRNA binds to its complementary sequence followed by cleavage of the DNA at two points. That is how the double stranded break is created.