CBIO 3400 Lecture Notes - Lecture 4: Crispr, Cas9, Base Pair
1 Apr 2019
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Document Summary
Bacterial adaptive immune system: crispr-cas9 invader immunity: crispr: clustered regularly interspace short palindromic repeat, certain regions in the genome that look strange short palindromic sequences (repeat. Serve as book ends to help separate the functional pieces. In b/w repeat regions, there are spacers: the different spacer regions correspond to foreign dna elements, cas genes- cas = crispr-associated genes. Class question: as a bacterium; how do you stop yourself from cleaving your own crispr. Doesn"t include a pam region in the repeat sequences. W/o pam region, you won"t cut your own genome. Pam is the signal to say this is the foreign piece. Never include a pam in the last bacterial phage that tried to kill you: cas9 scans for pam. If you don"t have a pam, cas9 will not stop at the region and pause to try to check. If you eliminate pam, cas9 will stop scanning. If you eliminate pam, there will be no cutting of the genome.
