Composite

Part:BBa_K3081023

Designed by: Xiaoying Qiao   Group: iGEM19_Peking   (2019-10-19)


pBAD-dCas9-J23119-ctrl

"This composite part is the principal design of the inducible CRISPRi system, with assistance of constantly expressed sgRNA that binds to the complementary coding sequence of mRFP. So it needs to cotransform with a plasmid coding mRFP. But the intended sgRNA ctrl can't bind to any sequence of mRFP coding region,so it's used as the control sgRNA. For more detailed information, see BBa_K3081024"

To investigate CRISPR-dCas9 binding specificity and affinity with DNA, we constructed arabinose-induced expression of dCas9 targeted to mRFP coding region, with assistance of constantly-expressed single guide RNA that is complementary to the corresponding sequence. Since normal mRNA elongation is interrupted by occurrence of dCas9, fluorescence is greatly decreased as the arabinose concentration increases, comparing to a single guide RNA that has no binding specificity to DNA. This proves the basic concept that a dCas9 protein is able to bind to DNA with sequence specificity and interferes with the physiological process. All plasmids we use to interfere with DNA replication subsequently are derived from this.

T--Peking--crispri.png

Figure 1. CRISPR-interference causes a rapid decrease in mRFP as the arabinose concentration increases. Target sequence of CRISPRi, NT1, is located on the coding region of mRFP. The control group, of which the sgRNA is composed of a Poly-adenine that has no binding affinity to DNA strand.

Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    INCOMPATIBLE WITH RFC[12]
    Illegal NheI site found at 1205
    Illegal NheI site found at 5459
    Illegal NheI site found at 5482
  • 21
    INCOMPATIBLE WITH RFC[21]
    Illegal BglII site found at 1470
    Illegal BamHI site found at 1144
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    INCOMPATIBLE WITH RFC[25]
    Illegal AgeI site found at 979
  • 1000
    INCOMPATIBLE WITH RFC[1000]
    Illegal SapI site found at 961


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Categories
Parameters
None