RNAi: Gene Regulation via miRNAs & siRNAs

The video tutorial explains RNA interference, focusing on microRNAs and small interfering RNAs (siRNAs) as key regulators of gene expression post-transcriptionally. It details the synthesis, processing, and function of microRNAs, including their export from the nucleus and interaction with the RISC complex in the cytoplasm. The tutorial highlights the role of Argonaute in unwinding RNA strands and the mechanisms by which siRNAs can lead to mRNA degradation or translation repression, depending on the degree of complementarity. The importance of this pathway is underscored by its discovery in C. elegans, which earned a Nobel Prize.

What is the primary function of microRNAs and small interfering RNAs in gene expression?

• To repair damaged DNA

• To initiate protein synthesis

• To regulate gene expression post-transcriptionally

• To enhance DNA replication

What is the general term used to describe the pathway involving microRNAs and small interfering RNAs?

• DNA replication

• Protein synthesis

• RNA interference

• Gene splicing

What structure is formed by the complementary binding regions in microRNA?

• Hairpin

• Double helix

• Loop

• Zigzag

Which enzyme complex is responsible for trimming primary microRNA in the nucleus?

• Dicer

• RNA polymerase

• DGCR8 and Drosha

• Argonaute

What is the role of Exportin 5 in the RNA interference pathway?

• To degrade mRNA

• To synthesize microRNA

• To bind to mRNA

• To export pre-microRNA from the nucleus

What is the primary function of the RISC loading complex?

• To synthesize DNA

• To replicate RNA

• To load a single strand of microRNA

• To degrade proteins

Which protein acts as a helicase to separate microRNA strands?

• Exportin 5

• Dicer

• TRBP

• Argonaute

What happens when the RISC complex finds an mRNA strand with perfect complementarity?

• The mRNA is translated into protein

• The mRNA is degraded

• The mRNA is exported from the cell

• The mRNA is replicated

What is the result of near-perfect complementarity between small interfering RNA and mRNA?

• Translation is repressed

• mRNA is translated

• mRNA is degraded

• mRNA is exported

What structural feature of Argonaute helps small interfering RNAs to bind?

• Chelation of metal cations

• Its ability to synthesize RNA

• Its double helix structure

• Its role in DNA replication