Double DNA in the Liver

What am I looking at?

This is a single human hepatocyte. Its two nuclei are in blue (1). The other colors in this image are stains of the actin protein and are depth-coded, with red being the closest to the viewer, then green, then orange, and finally yellow being the farthest from the viewer.

Biology in the background

Hepatocytes are involved in a range of important functions carried out by the liver, including protein synthesis and bile production. Bile aids in food digestion. Hepatocytes are involved in breaking down molecules normally found in the body, like hormones and vitamins, as well as foreign substances, like medicines, alcohol, and some toxic compounds.

Most cells in the body have only one nucleus. But about 40% of hepatocytes have more than one nucleus. This increase in the number of nuclei occurs when the last step of cell division (cytokinesis) fails, and the parent cell does not divide into two, leaving duplicated DNA inside a single cell. While this so-called “binucleation” is considered a cellular mistake, it is thought to aid in the function of hepatocytes.

The nucleus contains DNA, which forms the blueprint for the cell’s proteins. Researchers hypothesize that having two sets of blueprints might help hepatocytes more efficiently synthesize the proteins needed for different liver functions. This could come in handy for liver cells that need to produce proteins involved in protein synthesis and modification while also producing proteins that aid in the detoxification of the bloodstream.

In humans, hepatocytes can grow up to 30 micrometers, or roughly 2.5 times smaller than the width of a human hair.

Technique  

This image was created using confocal microscopy.