Regulatory

Part:BBa_K3453075

Designed by: Maeva Cherriere   Group: iGEM20_Evry_Paris-Saclay   (2020-10-24)


Truncated Grapevine VvTrnL-UAA Switch 1.1.2 (no trigger binding site)

This part is a truncated version lacking the trigger binding site of the Grapevine toehold switch 1.1.2 (BBa_K3453073). Thus this part mimics the open (unfolded) state of this toehold switch.

Usage and Biology

A toehold switch is an RNA–based device containing a ribosome binding site (RBS) and an ATG start codon embedded in the middle of a hairpin structure that blocks translation initiation [1]. The hairpin can be unfolded upon binding of a trigger RNA thereby exposing the RBS and the ATG start codon and thus permitting translation of the reporter protein (Figure 1).


T--Evry Paris-Saclay--toehold-switch.png

Figure 1. Toehold switches principle.

This part is a truncated version lacking the trigger binding site of the Grapevine toehold switch 1.1.2 (BBa_K3453073). Thus this part mimics the open (unfolded) state of this toehold switch. It's secondary structure predicted by NUPACK web server [2] using default parameters is represented in Figure 2 and here-after in dot-bracket notation.

............((((((((............))))))))..........(((....))).....
T--Evry Paris-Saclay--RNAstructure p58 TruncatedVvTrnL-UAA1-1-2.png

Figure 2. Secondary-structure prediction of this part with the ATG of the reporter gene. The prediction was realised using the NUPACK web server [2] with default parameters and graphically represented using the forna RNA secondary structure visualization tool [3]. Nucleotides were coloured to match the different segments in Figure 1.

The functionality of this part was tested using sfGFP-LVAtag (BBa_K2675006) as a reporter. The expression was controlled by the T7 promoter (BBa_K2150031) and the strong SBa_000587 synthetic terminator (BBa_K3453000) in the composite part BBa_K3453175.

This part proved to be functional: a readable output was generated in the presence and in the absence of grapevine RNA.

Full results are available on the BBa_K3453175 page in the registry.

References

[1] Green AA, Silver PA, Collins JJ, Yin P. Toehold switches: de-novo-designed regulators of gene expression. Cell (2014) 159, 925-939.

[2] Zadeh JN, Steenberg CD, Bois JS, Wolfe BR, Pierce MB, Khan AR, Dirks RM, Pierce NA. NUPACK: Analysis and design of nucleic acid systems. Journal of Computational Chemistry (2011) 32, 170–173.

[3] Kerpedjiev P, Hammer S, Hofacker IL. Forna (force-directed RNA): Simple and effective online RNA secondary structure diagrams. Bioinformatics (Oxford, England) (2015) 31, 3377–3379.


Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    COMPATIBLE WITH RFC[12]
  • 21
    COMPATIBLE WITH RFC[21]
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    COMPATIBLE WITH RFC[25]
  • 1000
    COMPATIBLE WITH RFC[1000]


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Parameters
None