Novel expression vectors enabling induction of gene expression by small-interfering RNAs and microRNAs

Area of Science:

• Molecular Biology
• Gene Regulation
• Biotechnology

Background:

• Small-interfering RNAs (siRNAs) and microRNAs (miRNAs) are small RNA molecules regulating gene expression post-transcriptionally.
• Synthetic siRNAs are molecular tools targeting specific genes, while endogenous miRNAs regulate gene expression in eukaryotes.
• Current applications of miRNAs include diagnostics and therapeutic strategies, including cell-specific inhibition of gene therapy vectors.

Purpose of the Study:

• To demonstrate for the first time that siRNAs and miRNAs can be utilized to induce gene expression.
• To engineer expression vectors capable of mediating siRNA- or miRNA-induced gene expression.
• To explore the potential of this system for therapeutic applications, such as cancer therapy.

Main Methods:

• Designed expression vectors with target sites for siRNAs or miRNAs located between a transgene and an Upstream Inhibitory Region (UIR).
• Utilized a UIR composed of seven open reading frames, identified as an efficient translation inhibitor.
• Investigated the cleavage of mRNA by siRNAs or miRNAs to separate the transgene from the UIR, enabling translation of the resulting uncapped mRNA.

Main Results:

• Both artificial siRNAs and endogenous miRNAs successfully induced transgene expression when incorporated into the engineered vector system.
• The UIR comprising seven open reading frames proved most effective in inhibiting downstream transgene translation.
• Demonstrated specific induction of cell death using the diphtheria toxin A-chain gene targeted by highly expressed miRNAs.

Conclusions:

• This study presents a novel method for inducing gene expression using siRNAs and miRNAs.
• The engineered vector system allows for controlled gene activation via RNA interference.
• The findings suggest potential applications in cancer therapy through targeted induction of cell death.