Immunofluorescent images of formaldehyde-fixed cell lines are shown. Three different organelle markers are displayed as different channels in the multicolor images - nucleus stained in blue, microtubules in red and ER in yellow. The various cell structures that are demonstrated are always shown in the green channel using an antibody found in the Human Protein Atlas. The antibody id is linked to the corresponding Cell Atlas protein page. By using the "toggle channels"-buttons, the different channels can be turned on and off. Most cell structures can be highlighted in the cell illustration by hovering over them with the exception of the aggresome. Cytoplasmic bodies are highlighted as cytosol; cytokinetic bridge, midbody, midbody ring and mitotic spindle are highlighted as microtubules, cell junctions are highlighted as plasma membrane and nucleus is highlighted as nucleoplasm.
Staining of nucleus in human cell line U-2 OS (HPA043786)
Scale bar represents 10µm
The nucleus is the largest organelle in the human cell and contains almost all the DNA in eukaryotic cells (the rest being found in the mitochondria). It is surrounded by the nuclear membrane, which isolates it from the rest of the cell. This ensures a highly controlled DNA replication and transcription without interference of the translation that takes place in the cytoplasm.
In the Human Protein Atlas the chemical 4',6-diamidino-2-phenylindole (DAPI) is used to counterstain the nucleoplasm, as it will bind strongly to DNA, and hence not stain the nucleoli. The immunofluorescent staining of proteins localized to the nucleus varies between different antibodies, in some cases staining the whole nucleus and in others the nucleoplasm. The staining characteristics can vary from a smooth to a punctate staining.