Where would we be without GFP?

In light of the yesterday's announcement of the 2008 Nobel Prize in Chemistry, I'd like to take a minute to demonstrate the importance of this work. The prize will be shared among Osamu Shimomura, Martin Chalfie, and Roger Tsien for the discovery and development of green fluorescent protein, GFP. Yep, that's right, good ole GFP finally getting the props it deserves. Truly, where would science and discovery be without GFP? I estimate that at least 50% of the cell sorting done in our facility is for GFP or its analogs (CFP, RFP, YFP, etc..), and I'm sure that scenario is repeated in every major Institution with a Flow Core. Even in simple flow cytometry analyses, GFP is many times one of the colors people typically look at. If you do a Pubmed search for keyword GFP, you'll get over 15,000 hits, and GFP hasn't even been around THAT long. I won't go into the history of GFP here, but if you're interested, just check out the wikipedia entry. If you're at all familiar with using GFP, then you undoubtedly have heard of or read papers by Roger Tsien, who not only did the early work on using GFP to label proteins in living cells, but has gone on to develop a whole slew of variants. These variants have different spectral properties and expression rates and stabilities, but they all pretty much work the same way. With the addition of many distinct fluorescent proteins, investigators now can label 3 or 4, or more proteins simulataneously in living cells. So, congratulations Shimomura, Chalfie, Tsien, and, of course, GFP.