Imaging techniques permit scientists to follow a day — or four — in the life of a cell

The movement and growth of cells are critical for normal physiological processes, and–when perturbed–can result in negative outcomes such as tumor formation. Understanding how live cells function is therefore invaluable for molecular and cellular biologists, and advanced techniques to visualize cells in action are of great importance.

The current issue of Cold Spring Harbor Protocols (www.cshprotocols.org) addresses these concerns with two freely accessible protocols: one for inserting 'reporter' proteins into cells to monitor what's going on inside, and another for maintaining the cells under a microscope for long-term observation.

The first protocol, available at

http://www.cshprotocols.org/cgi/content
/full/2007/1/pdb.prot4657, details a procedure to inject proteins into individual cells. The injected protein can be fluorescently labeled, so scientists can track the glowing protein with a microscope and observe what it's doing and where it's going inside the cell. This microinjection technique is similar to those that are used to create cloned and transgenic organisms, and it can also be applied to more complex assays–including laser photobleaching and fluorescent speckle microscopy–that yield specific insights into cellular processes.

A second freely available protocol

(http://www.cshprotocols.org/cgi/content/full/2007/1/pdb.prot4660) outlines the construction and use of an enclosed microscope chamber. This device is designed to optimize the culture environment for cells–allowing them to grow as they would normally–while optimizing the conditions for viewing them by microscopy. This enables researchers to monitor the cells under a microscope for long time periods (in excess of four days), during which the cells may divide multiple times and cycle through nearly all cellular functions. When coupled with the latest in image-analysis software, this technique allows researchers to gain a long-term perspective on events in the lives of cells.