Team:Arizona State/Project
From 2011.igem.org
Project
- Our project will have several stages, all pursuant to the general investigation and modularization of the CRISPR pathway:
- Proof of concept targeting reporters such as GFP, eventually creating a CRISPR biobrick
- Investigate CRISPR system dynamics based on factors such as degradation of self-targeting sequences and maintenance of the array.
- Target genes such as NDM-1 or other clinically relevant pathways.
The CRISPR Mechanism
CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) is a genomic feature of some prokaryotes and most archea. A CRISPR locus consists of a set of CAS (CRISPR associated) genes, a leader, or promoter, sequence, and an array. This array consists of repeating elements along with "spacers". These spacer regions direct the CRISPR machinery to degrade or otherwise inactivate a complementary sequence in the cell.
The CRISPR / CAS pathway can be viewed as a prokaryotic immune system or as an analogue to eukaryotic RNAi. This mechanism of bacterial survival can in theory be directed to silence a gene of interest, which affords us an interesting method to tackle the aforementioned problem. CRISPR gene loci have been demonstrated to equip both prokaryotes and archaea with a defense mechanism against exogenous DNA and RNA sequences [2], [10], usually targeting invading viruses. The transcripts from the spacer/repeat region undergo hair pinning due to the palindromic sequence structure. The peptide products of the CAS genes work cooperatively with crRNA to silence a complimentary target (Diagram 1) [4]. The function is a prokaryotic analog to both RNA interference and immunity. CRISPR presents it self as a potentially useful tool in prokaryotic gene manipulation. Our goal as ASU’s first iGEM team is to develop a CRISPR plasmid that contains elements to target and silence the NDM‐1 gene sequence (Diagram 2). While our final goal is the targeting of NDM‐1, we recognize that CRISPR can potentially target any gene of interest. We will develop a robust, modular platform for gene silencing based on CRISPR. The final product of this project will be a fully functioning CRISPR array that will be submitted to the Standard Registry of Biological Parts, an open‐source collection of DNA building blocks, as a BioBrick, a modular component for genetic engineering (Diagram 3).