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Dictionary > Cell structure > Nucleoli

Staining of nucleoli in human cell line PC-3 (HPA036506)
Scale bar represents 5µm


The nucleolus is a non-membrane bound organelle taking part in synthesis of ribosomes, including processing of rRNA and the assembly of them into ribosome subunits. It is also involved in several other cellular processes, such as mitosis, stress response and cell cycle regulation. Structurally, the nucleoli consists of three subregions; the fibrillar centers, dense fibrillar components and granular components (FC, DFC and GC).

Immunofluorescent staining

Nucleoli are usually stained as small, somewhat elongated circles in the nucleus. However, their staining pattern can vary from the nucleolus being completely stained, to only a small part of it, sometimes in a spotty pattern.

It is common that proteins are localized to both the nucleus and the nucleoli, with different staining intensity, as well as only the nucleoli.

Examples IF

Example 1
Example 2
Example 3
Example 4

Examples IH

Example 5