lncRNA - Lange niet-coderende RNA's

Long non-coding RNAs or lncRNAs can regulate gene expression and other cellular processes. They are widespread and are found in plants, animals, bacteria, and viruses; however, they show low sequence conservation between different species.

LncRNAs are RNA transcripts longer than 200 nucleotides that are not translated into proteins; however, most are processed the same way as precursor mRNA through splicing and the addition of a 5’ cap and 3’ poly-A tail.

Compared to protein synthesis, RNA synthesis takes less energy and occurs more rapidly. As RNA is produced in the nucleus, it can be immediately used for gene regulation and can provide a faster response than proteins, which need to be imported from the cytoplasm.

LncRNA can perform their functions through several different mechanisms. When present near DNA, lncRNA can act as a scaffold for proteins by forming multiple stem-loop structures where proteins can bind and carry out their function, like chromatin-modifying proteins or transcriptional activators and repressors.

Like microRNA, lncRNA can act as guide RNA where its one part binds to various protein complexes whereas another part can selectively base pair with target DNA region and thereby helps in localization of the protein complexes.   

LncRNA can act as alternative binding sites or sponges, sequestering some molecules away from their target location. For example, lncRNAs bind to microRNAs and prevent their interaction with their target mRNA.  

LncRNA can base-pair with a complementary region in mRNA. This base-pairing can inhibit pre-mRNA splicing by hiding particular splice sites or can block the translation of mature mRNA.

Some lncRNA also carry exons and produce small peptides of unknown function.

LncRNAs are emerging as a significant player in additional cellular processes such as chromatin modifications and epigenetic regulation, as well as several diseases such as cancer and neurological diseases