miRNA’s and RNA interference

Flashcards about gene expression and RNA interference, based on a university lecture.

Gene Expression

The process from DNA to RNA to protein, involving replication, transcription, and translation.

Transgene Induced Gene Silencing (TIGS)

The phenomenon where the addition of a transgene can silence the endogenous gene, leading to a loss of mRNA. Acts in trans and can be hereditary.

RNA interference (RNAi)

A process by which short interfering RNAs (siRNAs), generated from longer double-stranded RNAs, can modulate expression of mRNA by translation inhibition or degradation.

microRNAs (miRNAs)

Endogenously expressed type of short interfering RNAs that modulate mRNA expression and are processed from a longer pri-miRNA precursor.

Drosha

An endonuclease that processes double-stranded primary RNAs into short, ~70 nt pre-miRNA precursors for Dicer processing.

Dicer

An endonuclease that processes double-stranded precursor RNA to 21-23 nucleotide siRNA molecules.

RISC

Complex of proteins and RNA. Core component: Argonaute (Ago) proteins.

Argonaute (Ago) proteins

Core component of RISC. Processes the dsRNA to a single strand, delivers the siRNA to the 3’ UTR of its target mRNA, and determines the specific mechanism by which mRNA is inhibited.

siRNA mechanism

Full complementarity with 3’UTR binding site and almost always triggers AGO2-mediated degradation of mRNA.

miRNA mechanism

Induces translational repression by binding to partially complementary binding sites.