Paraspeckles

Paraspeckles are nuclear bodies found in the nuclei of eukaryotic cells. They are sub-organelles and are visible under a light microscope. The term "paraspeckle" was first coined in 1997 by researchers who observed these structures. They are dynamic entities that can change in size and number depending on the cell's physiological state. Paraspeckles are primarily composed of proteins and RNA molecules. One of the most abundant and characteristic proteins found in paraspeckles is NONO, also known as p54nrb. Other key components include PSPC1 and FUS. The assembly of paraspeckles is dependent on the presence of specific RNA molecules, particularly those with a specific secondary structure. These RNAs are believed to act as scaffolds, bringing the protein components together. The precise function of paraspeckles is still an active area of research, but several roles have been proposed. They are thought to be involved in regulating gene expression by sequestering specific RNA transcripts, thereby preventing their translation. Additionally, paraspeckles have been implicated in DNA damage response and repair pathways, as well as in the processing of long non-coding RNAs. Their involvement in various cellular processes suggests they play a significant role in maintaining nuclear homeostasis.