These are cells that I infected with a lentivirus containing the gene for green fluorescent protein under the control of a strong promoter. The strong promoter ensures that if the gene is in a cell, it’s pretty much always turned on, and thus always making green fluorescent protein. Green fluorescent protein, being what it is, makes these cells glow green under a certain wavelength of fluorescent light. The cells themselves are HEK 293 cells, which were originally derived from human embryonic kidney cells. At this point, they’ve been cultured so much as a cell line that they’re not very physiologically similar to normal human cells – but that does make them extremely easy to work with.
Taken with an Olympus confocal microscope. Another nerdy part of me was wondering if Flickr would pick up on the type of “camera” this image was taken with, but alas, it appears not.