Nucleolus

Nucleolus

The nucleolus is the largest structure in the nucleus of eukaryotic cells, where it primarily serves as the site of ribosome production. Nucleoli also have other important functions like the assembly of signal recognition particles and playing a role in the cell's response to stress.

Structure and Composition

The nucleolus is made up of proteins, DNA and RNA. It does not have a membrane, but is an accumulation of RNA and proteins within the nucleus. The nucleolus organiser regions of chromosomes, which harbour the genes for pre-rRNA, are the foundation for the nucleolus.

Function

The primary function of the nucleolus is to produce and assemble ribosome subunits. The nucleolus takes up around 25% of the volume of the nucleus. This structure is made up of two main components, the outer dense fibrillar component (DFC) and the inner granular component (GC).

Role in Disease

Alterations in the nucleolar structure and function are associated with several pathologies such as cancer, viral infections, and neurodegenerative disorders.

See Also

• Cell nucleus
• Ribosome
• Eukaryotic cell

References

Nucleolus Resources
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