Essay On Nucleolus

The core of the cell is the nucleus and the largest component of it is the nucleolus.

The nucleolus is found in all the eukaryote cells and it is a non membrane bound nuclear organelle.[1]

The nucleolus is a domain lacking membrane, which is high in proteins and RNA content.

The proteins continually moves between the nucleolus and the nucleoplasm because of the dynamics within the cell.

The structure of the nucleolus is divided into three main subcomportaments, which are the fibrillar center (FC), the dense fibrillar component (DFC) and the granular component (GC).

In several studies it was possible to discover that the nucleolus contains most of the cell’s genetic material, structured as multiple long linear DNA molecules.

The size of

The functions mainly for the nucleolus are RNA-related, and it was also detected the ability of RNA processing and assembly f ribonucleoproteins (RNPs)

Another role of the nucleolus is the ability to maturate, assemble and export RNP particles as signal recognition particle, telomerase RNPs and processing of precursor transfer RNAs and U6 small nuclear RNAs. [4]

An additional role in the regulation of the cell cycle was observed, where it manages the stress responses, telomerase activity, and aging. Sequestering or re-leasing some specific proteins in the nucleolus regulates this function.

It was always thought that the main function of the nucleolus was linked with the ribosome biogenesis and exportation of mRNA in yeast and mammalian cells, however in recent studies data it was demonstrated the ability of the nucleolus in plant cells in transcriptional gene silencing, mRNA surveillance, nonsense-mediated decay and mRNA export.

Eukaryotic ribosomal RNA genes are organized in large clusters, often involving hundreds or thousands of repeated genes, with each gene encoding one copy of the 18S, 5.8S and 25–28S rRNAs.