François Jacob – Messenger RNA (40/77)


With Monod we had reached- this is what I was mentioning earlier, the idea that in phage the repression happened on 30 genes. So it either happened on the messengers… It needed to happen on a structure where the genes were combined and joined. It was either the messenger, or the DNA. [MM] But the messenger itself hadn’t been seen by anyone. At the time there were ideas that were- Yes, that’s true, I shouldn’t be talking about the messenger at this point. It was either an intermediate… actually it was either an intermediate where all of the group’s genes were represented, or it was the DNA itself. Following that, Sydney and I started working together. How did it happen? [MM] If I remember correctly, it’s because you remembered Volkin and Astrachan’s results showing that there were short-lived RNA molecules. Yes, well I had completely forgotten Volkin and Astrachan, and so had Sydney. So we… I don’t quite remember how it happened. But during a discussion at Sydney’s, he had a room in his College. He was like any Englishman- they all have something in a College. He was in a very posh College, I don’t remember which one. So he had a room there. And one day, we were having a discussion with Francis, who had arrived, where precisely I told them about the experiments on in-conductance, that we had done in Paris, which lead to the idea that there necessarily needed to be an intermediate between the gene and the protein, on which everything was represented. And it’s following that… So we talked about it all and that’s when they both leapt up, saying- It’s Volkin and Astrachan. I had completely forgotten about Volkin and Astrachan. I knew they existed but I had completely forgotten about them. They were the ones who had made the link. And so from then on, Sydney and I decided to go to Pasadena to do that experiment. [MM] And it almost didn’t work? We had exactly 30 days. Because he had engagements. Max Delbrück had invited him, No, in fact, Max Delbrück had invited me and Meselson had invited him, that’s it. And so we found ourselves over there. We decided that was what we were going to do, and we had exactly one month. We had to leave on a specific day. And for 20 days, it absolutely didn’t work. Meaning that… the principle consisted in marking old proteins with sulphur and the new RNA with phosphor. And what we needed to show was that the new phosphor joined the old ribosome proteins. It absolutely didn’t work for two or three weeks, until one day when we were hanging around on the beach, Sydney suddenly leapt up and said- It’s the magnesium, we didn’t put enough magnesium. Because what were looking at was inside cesium radians. And so obviously, the cesium was completed with the magnesium’s divalent things, so much more magnesium was needed. We ran back to the lab, poured in tons of magnesium, and it worked. [MM] And it was an experiment that showed that the ribosomes could basically join any messenger RNA. That’s right. [MM] And at the same time, François Gros of the Jim Watson lab was showing the existence of the short-lived RNA. Well, he went about it in a different way. He showed that- Volkin and Astrachan were working with phage. And they were trying to find, and they found- I think François was the one who found this- that when you briefly marked the RNA with growing bacteria, there was a sort of RNA that was very quickly marked, and that had the same composition as a basic DNA and which wasn’t the same thing as ribosome 1. So it’s through two different ways that we reached the same conclusion.

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