Cells showing DNA, mitochondria and ER

Human melanoma cells growing in culture. They have been stained to show the DNA within the nucleui (blue), the mitochondia in red and the endoplasmic reticulum (ER) in green. Optical slices were taken of the whole cell and reconstructed to form this image. The ER have been labelled by transfecting the cells with green fluorescent protein tagged calreticulin.