2030
The nucleolus is contained within the cell nucleus.
The nucleolus is the largest structure in the nucleus of eukaryotic cells.
The nucleolus is the site of ribosome biogenesis.
It participates in the formation of signal recognition particles and plays a role in the cell’s response to stress.
Nucleoli are made of proteins, DNA and RNA.
Nucleoli form around chromosomal regions called nucleolar organizing regions.
Malfunction of nucleoli can be the cause of several human diseases.
There are 3 major components:
The fibrillar center (FC),
the dense fibrillar component (DFC),
and the granular component (GC).
Transcription of the rDNA occurs in the fibrillation center.
It is the site of ribosomal RNA (rRNA) synthesis, which is needed for ribosomal assembly.
The dense fibrillar component contains the protein fibrillarin, which is important in rRNA processing.
The granular component contains the protein nucleophosmin.
Nucleophosmin is involved in ribosome biogenesis.
In many nucleoli there is a clear area in the center of the structure referred to as a nucleolar vacuole.
The nucleolus, in addition to its ribosomal biogenesis, it captures and immobilizes proteins, a process known as nucleolar detention.
Detained proteins in the nucleolus are unable to diffuse and to interact with their binding partners.