Eukaryotic lncRNAs Flashcards
What are lncRNAs?
Non-coding RNAs that are over 200 nucleotides
How many lncRNAs do humans have?
About 30 000. They make up some of the non-coding transcriptome
Why are lncRNAs a heterogenous class of ncRNAs?
Different subtypes with different functions
What are the 3 subtypes of lncRNAs? How are they classified?
Based on position and direction of transcription relative to other genes. There are sense lncRNAs (same strand as their overlapping gene), antisense lncRNAs (opposite strand as their overlapping gene), and intergenic lncRNAs (not overlapping with a gene)
What are 2 functions of lncRNAs?
Regulating cellular/developmental processes, and can inhibit or activate gene expression through a variety of mechanisms
How many coding genes have an lncRNA regulating them?
Estimated that 25-40% of coding genes have an overlapping antisense lncRNA
Does size or function define what a lncRNA is?
Size
What are 5 mechanisms of action of lncRNA?
- Binding to miRNA and titrating them
- Direct chromatin modification enzymes
- Influences on transcription
- Post-translational modifications
- Regulate RNA processing
How do lncRNAs influence gene expression by binding to miRNAs and titrating them?
It removes miRNA so they don’t reach their targets, allowing the target gene to be expressed. These lncRNAs are called ceRNAs - competing endogenous RNA
How do lncRNAs influence gene expression by directing chromatin modifications?
They direct the enzymes to particular sequences
How do lncRNAs influence gene expression by influencing transcription?
Lots of mechanisms. Some are paRNA - promoter associated RNA
