Noncoding RNA Flashcards

Dr. Frank Stearns
BIO 330
Spring 2025

RNA can act as a regulator by forming secondary structures (either inter- or intramolecular).
These structures can control gene expression.

A riboswitch is an RNA molecule whose activity is controlled by a small ligand.
A ligand is any molecule that binds to another molecule.
The ligand might be a metabolite product.
A riboswitch may also function as a ribozyme.
Aptamer: An RNA domain that binds a small molecule, leading to a conformational change in the RNA.
Figure 29.1: The 5' untranslated region of the mRNA for the enzyme that synthesizes GlcN6P contains a ribozyme activated by the metabolic product.

Vast regions of the eukaryotic genome are transcribed on both strands.
Antisense gene: A gene that codes for an antisense RNA, which has a complementary sequence to a target RNA.

Antisense RNA: RNA with a complementary sequence to a target RNA.
Figure 29.3: Antisense RNA can be generated by reversing the orientation of a gene with respect to its promoter.

A regulator RNA can form a duplex region with a target RNA. This can:
- Block the initiation of translation.
- Cause termination of transcription.
- Create a target for an endonuclease.
Transcriptional interference (TI): Occurs when an overlapping transcript on the same or opposite strand prevents transcription of another gene.
Long ncRNAs (lincRNAs): Defined as non-coding RNAs longer than 200 nucleotides, lacking an open reading frame, and produced by RNA Pol II.

Nested gene: A gene located within an intron of another gene.
Some noncoding RNAs (ncRNA), such as CUTs and PROMPTs, are often polyadenylated and very unstable.
Figure 29.4: PHO84 antisense RNA stabilization is paralleled by histone deacetylase recruitment, histone deacetylation, and PHO84 transcription repression. (Data from J. Camblong, et al., Cell 131 (2007): 706–717.)