Part:BBa_K2206000

Toehold switch for hsa-miR-15b-5p

Toehold switches are synthetic riboregulators that regulate gene expression post-transcriptionally. Gene expression can be activated in the presence of a cognate single stranded RNA molecule that contains an arbitrary sequence (the trigger RNA). The trigger RNA binds to the switch through base pairing, causing a conformational change that results in translation of the downstream protein coding region.

This part codes for a toehold switch that contains a region that is complementary to the microRNA hsa-miR-15b-5p (the trigger RNA). In the presence of hsa-miR-15b-5p, translation of the downstream protein coding region occurs.

This part can be used to regulate the expression of any protein in response to the levels of hsa-miR-15b-5p present in a system.

The transcripts produced by this part are toxic to E. coli. Therefore, we recommend the use of an inducible non-leaky promoter to allow for amplification in E. coli. For reference, we found BBa_K808000 suitable for expressing this part.

See part BBa_K2206006 to see how this part works when regulating GFPmut3b.

This part contains a strong RBS sequence.

NUPACK Structure Analysis

Information contributed by City of London UK (2021)

This toehold switch was characterized in silico using the ToeholdTools project that our team developed. See https://github.com/lkn849/thtools for more information.

Metadata:

• Group: City of London UK 2021
• Author: Lucas Ng
• Summary: Used our software ToeholdTools to investigate the target miRNA specificity and activation of this part.

Raw data:

• Media:BBa_K2206000_thtest.txt
• Media:BBa_K2206000_crt.txt

This contribution was autogenerated by the script contrib.py, available at https://github.com/lkn849/thtools/tree/master/registry.

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This switch was designed to detect the miRNA hsa-miR-15b-5p at a temperature of 37°C. We tested it against every mature Homo sapiens miRNA in miRBase and our analysis shows that at this temperature it is best used to detect hsa-miR-15b-5p.

With hsa-miR-15b-5p at 37°C, the switch has a specificity of 81 ± 30 % and an activation of 16 ± 7 %. These values represent 95% confidence limits (z=1.96).

The temperature–activation–specificity relationship is shown here. CRT is an acronym for CelsiusRangeTest, the class in our Python library responsible for the following graph:

Error bars represent the standard deviation. The line of best fit was calculated using a univariate cubic spline weighted inverse to each point's standard error.

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]