Non coding RNAs Flashcards
What are the types of non-coding RNAs?
Small: miRNA, piRNA, tiRNA;
Mid size: SnRNA;
Long: lncRNAs
When did the discovery of non-coding RNAs begin?
In the mid 2000s with the start of RNA sequencing.
What is the biogenesis of microRNAs?
Transcribed by RNA polymerase II into a hairpin loop structure, recognized by Drosha.
What role does Drosha play in microRNA biogenesis?
Drosha cleaves off the end of the hairpin loop.
How are microRNAs exported to the cytoplasm?
Exported by exportin proteins (EXP5).
What happens to microRNAs in the cytoplasm?
Recognized by Dicer, which cuts off the hairpin loop to form dsRNA.
What is the function of Ago proteins in microRNA processing?
They choose one strand of miRNA and find mRNA with a complementary sequence.
What is the role of microRNAs in gene regulation?
They repress translation of mRNA while bound, acting as an on/off switch.
What is a seed sequence in microRNAs?
The sequence that matches with mRNA, specific for a set of mRNA targets.
How can microRNAs be used in cancer treatment?
They can target mRNA of tumor suppressor genes or oncogenes.
What is the significance of miR21 in cancer?
miR21 over-expression leads to large tumors; its removal causes tumor shrinkage.
What percentage of non-coding RNAs do long non-coding RNAs represent?
68% of non-coding RNAs.
What are the major categories of long non-coding RNAs?
Sense, Antisense, Intronic, Bidirectional, Intergenic.
What are the functions of long non-coding RNAs?
They can bind to DNA/RNA, recruit proteins, act as decoys, signals, scaffolds, or guides.
What is FIRRE and its role?
Interacts with protein hnRNPU to bring together areas on chromosomes for simultaneous transcription.
