This year's Nobel Prize in Chemistry went to the discoverers and developers of green fluorescent protein (GFP), widely used in biology to trace cellular processes.

Nobel laureate Martin Chalfie of Columbia University in New York.University of Columbia/Eileen Barroso

Nature News caught up with an excited Martin Chalfie of Columbia University in New York, who showed that the gene for GFP could be expressed in other organisms. He shares the prize with Osamu Shimomura, now an emeritus professor at the Marine Biological Laboratory in Woods Hole, Massachusetts, and Roger Tsien at the University of California, San Diego.

How did you find out about the prize?

This is a bit of an embarrassment. A couple of days before the announcement I had been playing around with our phone. I must've hit a wrong button and changed the ring so that it turns out to be fairly faint. So I slept through the call [from the Nobel committee]. I woke up a little after 6 o'clock in the morning and, realising that the announcement must have been made, I opened up my laptop and went to the Nobel Prize website to see who had won. I saw my name and I nudged my wife and said, "I think you'd better look at this".

The work on green fluorescent protein had been widely tipped as a Nobel Prize contender. Would you have been disappointed if you hadn't won at some point?

That's a very hard thing to say. When one does a piece of work that other people enjoy and talk about, you always get some people that come up to you and say: "I really like this work. I think this is a prize-worthy piece of research". If enough people tell that to you, you begin to wonder yourself. And it means you get a little nervous around October.

Why did you start working on GFP?

Since my postdoc in the late 1970s and early 1980s in Sydney Brenner's lab in Cambridge, UK, I have worked on the nematode Caenorhabditis elegans.

Whenever we went out to give seminars about C. elegans, we always spoke about how wonderful the animal was, because it grew quickly, it was small, we knew what the cells were, we had the reconstruction of the lineage and the nervous system. And we always said, "and the animal is transparent".

I first heard about GFP in late 1988, or early 1989 when I attended a seminar by a scientist named Paul Brehm [now at the Vollum Institute, Portland, Oregon]. He described aequorin, the light-producing protein from jellyfish that Shimomura had also discovered, but he also mentioned this fascinating protein called green fluorescent protein.

When somebody who has been saying for 12 years that an animal is transparent hears somebody talk about a fluorescent protein, suggestions come to mind. I immediately thought that this was going to be a way of looking at gene expression and to look at protein localizations. And so I was very excited, in fact I don't remember anything else about Paul's seminar. That's when I first got in touch with Douglas Prasher, because I knew that if we could get this we could use it as a marker for cells and it would be extremely useful.

Douglas Prasher isolated the gene that expresses GFP while he worked at the Woods Hole Oceanographic Institute, Massachusetts, and there have been suggestions that he should have been awarded part of the prize. What is your feeling on that?

My feeling is that yes, he should have been. The problem is that the Nobel Prize is given to a maximum of three people. I would have assumed that the academy debated long and hard about people's contributions.

Douglas was intimately involved. He was the last author on the paper that I published in Science describing the first uses of GFP as a biological marker. He is on the first paper that Roger Tsien published as well. His work was crucial to what we did. So I think his contribution to the science has been massive, and very important. I can only imagine that the selection committee agonized over who should be awarded this prize, with the restriction that they can only have three. I regret that that is the case.

By injecting GFP into embryonic pigs, researchers managed to breed three male transgenic pigs.National Taiwan University/ REUTERS

Do you have a favourite application of GFP?

Not really. We've used it in many ways in my research to look at gene expression and protein localisation; we've used it as a basis of genetic screens to identify mutations that affect nerve development; we've used it as a way of isolating cells by cell cycle, by fluorescence-activated cell sorting; we've used it as a way of marking cells for electrophysiology.

One proposed application I know that several people have tried is to see if they could hook up bacterial promoters that would respond to increased levels of TNT [trinitrotoluene], and use that to drive the expression of GFP. The idea behind this is that you scatter bacteria or plant seeds [on the ground]; if they fall near a landmine that was leaking TNT, that would allow for the expression of green fluorescence, and one could go at night with a UV lamp and actually see where the TNT was leaking so that people wouldn't be maimed by landmines. That's a very wonderful use if it can be developed.

What's next for you?

I suspect that there'll be a couple more interviews, then things will start to calm down. The funny thing is, some people ask: what are you going to do now? But this was an award for something that we published 14 years ago. We've been doing quite a lot [since then], mainly looking at mechanical sensors on the sense of touch and trying to understand how that's transduced.

We're going to continue to work on that. So I hope that, except for a couple of celebrations, it's going to be fairly normal.