United Kingdom
April 10, 2012
In a series of three articles, BBSRC Innovator of the Year 2012 winners reveal the secrets behind their innovations.
In this, the first, Professor George Lomonossoff (photo) of the John Innes Centre explains how a safe and accessible way to make proteins in plants could revolutionise vaccine screening and yield novel metabolites. In the second, Professor Jim Murray of the University of Cardiff describes how new DNA detection technology using light could improve on-the-spot medical and food diagnostics. In the third, Professor Russell Foster explains how discovering an entirely new class of photoreceptor in the eye transformed our understanding of how body clocks regulate healthy ageing.
In 2009 BBSRC established the annual Innovator of the Year competition to celebrate scientists who delivered science with high economic and social impact. See 'The money of all invention' for details on how innovation powers the technological treadmill that can solve both local and global problems, drive economic growth, and make our lives longer, easier and happier.
Congratulations! How does it feel to win?
It's actually very pleasant indeed. You go into these things thinking you have a chance. However, you don't dare to think you may be the winner.
Were you surprised to win?
It's an odd one. I always thought I was in there with a shout, but I was genuinely shocked by the announcement. You don't get to see other candidates' presentations, so you're in a bit of a vacuum in that sense.
Describe your innovation in your own words...
When you want to make a protein you make an mRNA [delivered by a plant virus into the plant] that is translated into protein by ribosomes. What we've done is found a method for making the translation of those mRNAs extremely efficient.
What myself and Frank Sainsbury (former PhD student and Innovator co-winner) found was that if you included a suppressor of the gene silencing which knocks down the RNAi pathway, then you stabilise the mRNA so much that you don't gain much more expression by viral replication.
How does it work?
It stems from a number of years of research on the use of plant viruses as gene vectors for protein expression in plants. For many years, we, along with many others, assumed that to get high levels of protein expression in plants you would need replicating viruses. People used different viruses and various methods but it always relied on virus replication.
Frank Sainsbury in particular did some mutagenesis studies around a region (the 5' untranslated region) right at the beginning of the viral messenger, a region you need to preserve to get replication, which we hadn't touched up until then. We thought we'd need to make some alterations to make cloning into the vectors easier. Unexpectedly, some of the mutations Frank made showed massively enhanced translation from the RNA. So you didn't need replication anymore as you had made the RNA hypertranslatable.
JIC colleague's composite image beautifully illustrates the 'proteins from plants' principle.
Note virus particles in the liquid drop. Image: Eva Thuenemann
So it was one of those discoveries that was a bit of an accident?
Yes, it's based on a background of work but we didn't expect that phenomenon.
How is this different to normal, viral-induced protein production?
It's much more efficient because your mRNA doesn't require amplification by replication machinery.
The problem with a [viral] replication system, which everyone has come up against, is that if you copy RNA to RNA it's not a very faithful process – you build up errors and mutations very quickly and large chunks of the gene you want to express often get deleted. The other problem with replication systems is that if you have more than one RNA molecule replicating in the same cell they compete and eventually one will dominate. You could put in two, three or four RNAs to make a complex protein, but in most cases you only get one of them.
What is the technology for?
What it's really very good for is the rapid, transient protein expression in plants – as when you need a result very quickly.
The classic way of expressing foreign proteins in plants is transgenics [genetic modification] where you actually transform the plant and add genes. And that can take weeks or months or years. With transient expression you take your gene of interest, use an agrobacterium [with a DNA plasmid] to transfer it into the nucleus of a plant. And all you have to do is infiltrate a leaf with a suspension of bacteria using a syringe without a needle, or under vacuum. It's very simple, almost too good to be true.
What other advantages does your system have?
This work does not have to occur under a high degree of containment, or on premises licensed to handle viral pathogens. So it's a lot cheaper, and much more accessible to the worldwide research community.
Why rapidly express proteins in plants?
The technology is great for screening, especially when you want to make a lot of protein variants on a small scale very quickly.
The people who have really adopted it are a company in Canada called Medicago who are very interested in using it to make flu vaccines. In particular for rapid response situations, such as seasonal flu when you identify a new strain, and can very rapidly express the immunologically important proteins, such as haemoglutanins, in plants.
So when the race is on to produce candidate vaccines and they have used this system to produce candidate, experimental vaccines only two weeks after receiving genomic sequence data.
As well as getting successful expression, the other great thing about our system is that you get your failures very quickly! Therefore, you don't waste time on dead ends.
Has Medicago been the only interested company?
No, not at all. There are many uses of this technology so we wanted to get this out to as wide a variety of users as possible, including both academic labs and commercial companies.
When we first observed the effect in September 2007 it was so dramatic that we approached Plant Bioscience Ltd [PBL, a private technology transfer company owned by the John Innes Centre (JIC), BBSRC and The Sainsbury Laboratory] and filed a patent in January 2008. PBL operate a tech scheme, like a 'try before you buy', so I've sent kits to various companies and offer support info.
We've sent it to more 120 academic labs worldwide – that's been great as all sorts of things I'd never have thought of trying to express have been investigated – it's just a genuinely useful technique.
What kind of further impacts could the technology have?
The great help with working at a place like JIC is that there are different groups working on different aspects of plant biology. So we've used the system to alter plant metabolism. You can express enzymes whose function you don't know, and look at the novel products being made, and understand and analyse the metabolic pathways. And you can potentially mix and match enzymes from different sources and make 'new-to-nature' compounds. Then you can screen them very rapidly in Nicotiana benthamiana [a close relative of the tobacco plant used widely in research]. For instance, when you know gene sequence but want to ask: what is the activity here? Does this gene really exist or do anything?
How long have you been working on this?
Since the hypertranslation effect was discovered; that's just over four years. Before that I conducted a lot of background work on the virus – Cowpea Mosaic Virus (CPMV). I've worked on that for 30 years at JIC – how it works as a pathogen, how it multiplies, what its particles look like. A lot of basic science so you can start to manipulate bits of it; all culminating in this work in the last four years.
That must be very satisfying feeling after 30 years' work...
Very much so. But I'm a great believer in what I call a virtuous cycle. In that when you try to apply some of your basic knowledge, you often find that it doesn't work in quite the way that you think. They are not divorced from each other, the fundamental and the applied I think, but they reinforce each other.
What specific BBSRC grants have you used along the way?
JIC is aided by a long-term strategic grant from BBSRC. We've also had money from the Tools and Resources Development Fund, which was used for development of technologies such as the vector systems we made. We realised we needed to make them user-friendly as the vectors we used for the initial work were rather cumbersome. I take my hat off to Frank and Eva Thuenemann who, during their PhD studies, made a wonderfully streamlined series of vectors, very easy accessible and quick, which is why the use of our expression system has taken off so rapidly.
And taking it further some funding to produce empty nanoparticles or nanoshells has been obtained under a BBSRC Industrial Partnering Award. In addition, althougjh Frank's PhD was a rotation studentship with funding from several sources the research all took place in a BBSRC-funded institute.
When did you first become interested in science?
My first interest was astronomy when I turned a telescope to the skies aged ten or eleven, and then decided I was more interested in biology. I always wanted to do research; perhaps inspired by the Beatles' song Maxwell's Silver Hammer that has the line "late night all alone with a test tube". I rather liked the explanation angle of science and also the lifestyle – I envisaged not having to be terribly regulated and doing new things which other people hadn't done – that looked a bit a bohemian, suitable for the time in the 60s! I've been very lucky that I've been able to do it.
And it's all gone mostly well since then?
I've had a very enjoyable career in science. I didn't think I'd necessarily do something that would be practically useful. But nothing would make me happier than practical application for the good of society, I guess.
What's next?
Good question. Carry on exploring ways that we can use this technology. Originally it was all developed for transient expression, but another student in my group, Pooja Saxena, has shown that by modifying the suppressor of gene silencing you can make stable transgenic plants. The original suppressor prevented the regeneration of transgenic plants because it interferes with the development pathways. The mutation turns down the suppressor activity a notch or two, so you can now use our expression system to produce transgenic plants with high levels of your target gene.
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