- Protospacer = The foreign DNA corresponding to the spacer
DNA
- This is flanked by a conserved motif (Type I & Type II) called Spacer Acquisition (Immunization/Adaptation)
PAM (2-5 bp in length)
- PAM involved in acquisition (integration), though it is not - Specific fragments or protospacers (with adjacent
inserted into the CRISPR array, and also involved in protospacer-associated motif; PAM) of dsDNA from a
interference/immunity (cleavage of foreign DNA) virus or plasmid are recognised and
- Mutations in PAM allow viruses to escape CRISPR acquired(integrated) at leader end of a CRISPR array on
immunity host DNA by the action of Cas proteins
- Each CRISPR system is very specific in terms of what PAM Protospacers &
- PAM serves as recognition motif required for acquisition.
it will target PAM
- Cas 1 & Cas 2 are required (universally present in all
CRISPR/Cas systems)
Importance of PAM: - The Cas 1/Cas 2 complex integrates the protospacer at
- PAM is only found on foreign DNA and not on host DNA, the leader end of the array
therefore allows: - The CRISPR array consists of unique spacers;
- Spacer selection and acquisition interspaced between repeats; spacers with the most
- Discrimination between self & non-self recently acquired spacer are closest to the leader.
- Targeting protospacer for cleavage
- Mismatches at 3?end of protospacer and/or in PAM allow
foreign DNA to escape cRNA Expression & Processing
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through EFT, credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller mattclothier13. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for R133,00. You're not tied to anything after your purchase.