Final answer:
Long noncoding RNAs (lncRNAs) are involved in various cellular processes, including the regulation of gene expression through RNA interference (RNAi) and potentially coding for short peptides. They function to control mRNA stability and protein synthesis, contributing to the complex regulation of gene expression and cellular function.
Step-by-step explanation:
Long noncoding RNAs (lncRNAs) are a diverse class of RNA molecules that do not encode proteins but have various functions within eukaryotic cells. These include transcripts from antisense, intronic, intergenic, pseudogene, and retroposon DNA. Not all lncRNAs have known functions, and while some may be non-functional, others are important in regulating gene expression.
lncRNAs can interfere with the function of specific mRNA molecules, which are essential intermediaries between DNA and protein synthesis. They do this by participating in RNA interference (RNAi), which prevents mRNAs from guiding protein synthesis through base pairing with antisense RNA molecules. This can lead to rapid degradation of the target mRNA by the RNA-induced silencing complex (RISC).
Additionally, some long non-coding RNAs may contain short open reading frames (smORFs) and could be translated into short peptides, suggesting the human genome may have more protein-coding genes than previously thought. These RNAs play a role in various mechanisms of post-transcriptional regulation, including the modulation of polypeptide translation and turnover rates of specific RNAs and proteins.