Summary
RNAs longer than 200 nucleotides that regulate chromatin and gene expression, such as XIST.
In depth
lncRNAs can act as scaffolds, guides or decoys. XIST coats one X chromosome for inactivation, HOTAIR guides repressive complexes. Many are poorly conserved and their functions are still being studied.
lncRNAs are over 200 nucleotides long, and tens of thousands have been annotated. Many are expressed in a tissue-specific way and are transcribed by Pol II, spliced and polyadenylated, but do not encode proteins. Mechanisms include recruiting chromatin modifiers, sponging miRNAs, forming nuclear structures such as paraspeckles (NEAT1) and regulating enhancers.
Their functional significance is debated since some lncRNAs are transcriptional noise, but knockouts of some, such as Xist, Hotair and Malat1, show clear roles. Altered lncRNAs appear in cancers and heart disease.
Key idea: not all genes encode proteins, and a large part of the genome is transcribed into RNAs with regulatory roles.
Frequently asked questions
What is Long Non-Coding RNA?
RNAs longer than 200 nucleotides that regulate chromatin and gene expression, such as XIST.
Which area of biology covers Long Non-Coding RNA, and how advanced is it?
Long Non-Coding RNA is one of the 52 topics in Molecular Biology. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Enhancers and Silencers, microRNA, Transcription Factors.
Can you give an example of Long Non-Coding RNA?
XIST expression is the trigger of X inactivation in females.
What should I learn before Long Non-Coding RNA?
Work through the Beginner topics in Molecular Biology first, such as Central Dogma, DNA Replication, Base Pairing, then return to Long Non-Coding RNA. Advanced topics assume the Intermediate vocabulary.
What topics are related to Long Non-Coding RNA?
The closest topics to Long Non-Coding RNA are Enhancers and Silencers, microRNA, Transcription Factors, Gene Expression. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Long Non-Coding RNA?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Long Non-Coding RNA. To practise the whole of Molecular Biology, use the Molecular Biology quiz.
How is Long Non-Coding RNA different from Enhancers and Silencers?
Long Non-Coding RNA: RNAs longer than 200 nucleotides that regulate chromatin and gene expression, such as XIST. Enhancers and Silencers: Distant regulatory DNA elements that increase or decrease transcription via looping to the promoter. Read both side by side and note what each one explains.
How should I study Long Non-Coding RNA step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Enhancers and Silencers and explain the difference aloud. Finally, take the Molecular Biology quiz and come back to this page for any question you miss.