Part:BBa_K5310022
T3 hairpin arm
INTRODUCTION
The use of miRNAs as biomarkers and therapeutic molecules is seeing rapid advancements in the last decade. As a continuation of this, it is possible to combine the two functions with a mechanism that detects certain signature miRNAs of the disease and releases miRs with restorative effects based on a technique called Hybridization Chain Reaction.
MECHANISM OVERVIEW
The mechanism consists of two types of nucleic acid hairpins, a set of HCR hairpins and a T-shaped one. The first HCR hairpin is activated by an initiator molecule triggering a series of unbindings and hybridizations resulting in the release of two therapeutic molecules. The T hairpin recognizes the biomarker miRNAs and undergoes gradual unbinding of its arms upon which the initiator is released. It operates as a safety measure to make sure the HCR procedure mentioned above occurs in the right cells or tissue, where the therapeutic miRNAs should execute their function.
Different conditions are characterized by a different miRNA expression profile. It is therefore necessary to carefully select those according to which the hairpins would be designed. In the case of Multiple Sclerosis with the purpose of remyelination, one should examine which miRNAs are overexpressed in patient oligodendroglia (myelin generating cells) and which have the ability to enhance their desired function, while taking hairpin structure requirements into account. Upon literature review, discussions with neurologists and in silico testing, it was concluded that miR-125a-3p and miR-146a-5p are the biomarkers the T hairpin would be based on, whereas miR-219-5p and miR-338-3p are the remyelinating miRNAs released by HCR.
PART FUNCTION
This part was designed both to fit the structural requirements of the T hairpin (which is comprised of three arms;T1,T2,T3) and to operate as an initiator for the HCR technique (which is comprised of four hairpins; H1,H2,H3,H4). It is complementary to the T1 (BBa_K5310020) and T2 arms (BBa_K5310021).T1 and T2 bind to miR-125a-3p and miR-146a-5p respectively and are released, which leaves the T3 arm exposed. As initiator, it binds to the 3' end of the first HCR hairpin(H1) and causes it to unfold and bind to the next arm, setting the mechanism in motion for the subsequent release of the therapeutic miRs.
Sequence and Features
- 10INCOMPATIBLE WITH RFC[10]Illegal EcoRI site found at 17
- 12INCOMPATIBLE WITH RFC[12]Illegal EcoRI site found at 17
- 21INCOMPATIBLE WITH RFC[21]Illegal EcoRI site found at 17
- 23INCOMPATIBLE WITH RFC[23]Illegal EcoRI site found at 17
- 25INCOMPATIBLE WITH RFC[25]Illegal EcoRI site found at 17
- 1000COMPATIBLE WITH RFC[1000]
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