Noncodes

Noncodes, also known as non-coding RNAs (ncRNAs), are RNA molecules that are not translated into proteins. Unlike messenger RNAs (mRNAs), which carry genetic information from DNA to ribosomes for protein synthesis, ncRNAs perform various regulatory and structural functions within the cell. This class of RNA was once considered transcriptional "junk" but is now recognized as critical for cellular processes.

The discovery and characterization of ncRNAs have expanded significantly with advancements in genomics and transcriptomics. These molecules vary widely in size and function, with some of the most well-studied examples including ribosomal RNAs (rRNAs) and transfer RNAs (tRNAs), which are essential for protein synthesis itself. Other important ncRNAs include microRNAs (miRNAs), small interfering RNAs (siRNAs), and long non-coding RNAs (lncRNAs).

MicroRNAs and siRNAs are typically short RNA molecules that play crucial roles in gene regulation, often by binding to complementary mRNA sequences and inhibiting translation or promoting mRNA degradation. Long non-coding RNAs are longer than 200 nucleotides and can have diverse functions, including acting as scaffolds for protein complexes, regulating gene expression through epigenetic mechanisms, and influencing chromatin structure. The study of noncodes continues to reveal new insights into the complexity of gene regulation and cellular function.