Difference between revisions of "Part:BBa K1602052"

Latest revision as of 21:38, 25 September 2015

RRhoK

Composite part consisting of RRKey (BBa_K1602049) cloned upstream of RRlocked (BBa_K1602050).

RRhoK is a riboregulator-system controlling the expression of the polypeptide hokD (BBa_K1497008) and can be utilized as a killswitch for E.coli.

The expression of hokD is controlled by a constitutive promoter (BBa_J23100) but is repressed post-transcriptionally by the addition of a cis-repressing sequence (crRNA) upstream of the hokD sequence. When transcribed the crRNA forms a hairpin-secondary-structure masking the ribosome binding site (RBS) and therefore prevents translation of the following hokD-sequence.

If the corresponding trans-activating RNA sequence (taRNA) is present crRNA and taRNA fold into a RNA-RNA-complex. This leads to a helix shift and the release of the RBS enabling the expression of hokD resulting in cell death (Fig.1)

**Figure 1:** Interaction of taRNA and crRNA leads to expression of hokD.

RRhoK must be cloned downstream of any inducable Promotersystem. The promoter than controls the production of taRNA so that the conditions for activating the killswitch can be chosen individually by selecting an appropriate promoter system.

Sequence and Features

Assembly Compatibility:

10
COMPATIBLE WITH RFC[10]
12
INCOMPATIBLE WITH RFC[12]
Illegal NheI site found at 86
Illegal NheI site found at 109
21
COMPATIBLE WITH RFC[21]
23
COMPATIBLE WITH RFC[23]
25
COMPATIBLE WITH RFC[25]
1000
COMPATIBLE WITH RFC[1000]

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 The expression of hokD is controlled by a constitutive promoter (<html><a href="/Part:BBa_J23100">BBa_J23100</a></html>) but is repressed post-transcriptionally by the addition of a cis-repressing sequence (crRNA) upstream of the hokD sequence. When transcribed the crRNA forms a hairpin-secondary-structure masking the ribosome binding site (RBS) and therefore prevents translation of the following hokD-sequence.
-If the corresponding trans-activating RNA sequence(taRNA) is present crRNA and taRNA fold into a RNA-RNA-complex. This leads to a helix shift and the release of the RBS enabling the expression of hokD resulting in cell death (Fig.1)
+If the corresponding trans-activating RNA sequence (taRNA) is present crRNA and taRNA fold into a RNA-RNA-complex. This leads to a helix shift and the release of the RBS enabling the expression of hokD resulting in cell death (Fig.1)
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