Regulatory

Part:BBa_K4642014

Designed by: Ryan Yapa   Group: iGEM23_City-of-London-UK   (2023-09-28)


Gen4 486-19b-1260a Double AND-Gate Toehold Switch

Toehold switches are a class of de-novo-designed riboregulators that enable posttranscriptional activation of protein translation through mechanisms employed in artificial systems rather than natural ones. Unlike conventional riboregulators, the switches take advantage of toehold-mediated linear-linear interactions developed in vitro to initiate RNA-RNA strand displacement interactions. Furthermore, they rely on sequestration of the region around the start codon to repress protein translation, eschewing any base pairing to the RBS or start codon itself to regulate translation.

As a result, toehold switches can be designed to activate protein translation in response to a trigger RNA with an arbitrary sequence, enabling substantial improvements in component orthogonality. The absence of binding to the RBS and use of thermodynamically favourable linear-linear interactions also enables facile tuning of translational efficiency via RBS engineering. Consequently, these systems routinely enable modulation of protein expression over two orders of magnitude.

This toehold switch upregulates the translation of a reporter protein in the CDS downstream in the presence of micro-RNAs hsa-miR-486, hsa-miR-19b and has-miR-1260a - miRNAs upregulated in PCOS patients. When the miRNAs are present, they bind to parts BBa_K4642015 and BBa_K4642016, synthetic anti-miRNAs we designed, forming a complex which itself would act as a trigger.

Once the complex has formed, the 1260a section binds to the 1260a binding site, partially unfolding the switch, then the first anti-miRNA binds to the first anti-miRNA binding site, further unfolding the switch, then the hsa-miR-19b and the second anti-miRNA, before finally the hsa-miR-486 section unfolds the switch fully, exposing the RBS and start codon and allowing translation to occur at a ribosome. In a composite, a reporter gene should be placed downstream here which will report when in the 'on' state.


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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