In his final year at school, Trevor studied English, Biology, Chemistry, Pure Mathematics and Applied Mathematics.
Trevor is a graduate of LaTrobe University, from which he has obtained a BSc (Hons) and a PhD in Biochemistry.
After finishing his PhD, Trevor worked in the University of Basel in Switzerland before he returned to an academic appointment in Biochemistry at La Trobe.
Trevor is married to Michelle and they have three children, Sean, Anna and Patrick. All three children are in primary school, Sean the oldest is in Grade 5. Thanks to their time in Switzerland, all the Lithgow kids speak German.
For relaxation, Trevor enjoys cricket, swimming, snorkelling, cross-country skiing or listening to all sorts of music. There is usually music coming from Trevor's lab. in biochemistry ... ranging from Pearl Jam to Puccini.
Interviewer: Can you describe briefly how you are doing whatever you do?
Dr Lithgow:We put a gene which has a role in cancer in humans into yeast cells and look at the effect of the gene and its protein product there. To do this we prepare the human gene, called BCL-2, with a restriction enzyme to give it sticky ends. The yeast plasmids are cut with the same restriction enzyme. Then we use DNA ligase to insert to BCL-2 gene into the plasmids. The plasmids are returned to yeast cells and we investigate the effects of the gene product on the yeast.
Interviewer: Who or what (animal or plant) will benefit from your research/techniques?
Dr Lithgow: Humans with cancer will benefit if this research leads to effective treatment without too many unpleasant side-effects. Once we can do this for humans, the veterinary scientists are sure to use it for other animals too.
Interviewer: What are the economic implications of your applied genetics? (How expensive is it to do? What will be/are the cost benefits of the outcome?)
Dr Lithgow: A more effective treatment for cancer will have economic benefits to society if people are less ill for less time. Of course the treatment will still cost money, but the overall effect will be to save money.
This work, which is going on in a collaborative effort between Dr Andrea Strasser's group at the Walter and Eliza Hall Institute for Medical Research in Melbourne and some of us here at La Trobe Biochemistry, is funded by a grant from the National Health and Medical Research Council.
Interviewer: Historically, what is the scientific background to the research you are now doing?
Dr Lithgow:
Scientists have known about apoptosis since last century, but they had little information on its mechanism. With the development of the new techniques in biotechnology, it has become possible to search for and link genes with their function. The first gene associated with apoptosis was identified in 1988 at the Hall Institute. The gene, called BCL-2, has been discovered to inhibit apoptosis. So if gene BCL-2 becomes permanently 'switched on' for some reason, the cell with the 'stuck' gene ignores all of the normal triggers to die, it becomes immortal. Such a cell continues to divide by mitosis, and its progeny will also inherit the 'stuck' gene. These cells accumulate and eventually lead to a form of cancer. This was first found to occur in white blood cells, leucocytes, and it explains one of the causes that lead to leukemia.
With the techniques of gene transfer available now, we decided to put the BCL-2 gene into yeast cells and see if we could work backwards from there. Yeast cell don't get cancer. But we wanted to use the yeast as a very simple model to see what the human BCL-2 gene would do in these simple cells.
Interviewer: For a Year 12 Biology student to understand what you are doing, some background knowledge of biological concepts will be needed. Can you tell me what biology is relevant to what you are doing, and why?
Dr Lithgow: In the human body all cells are kept under some sort of control. Since we are working on what happens when cells don't die when they should, and asking why they go on to multiply out of control, students need to understand the normal cell cycle, and the process of mitosis which causes somatic cells to multiply.
In understanding mitosis, students also need to understand the structure of DNA, and particularly, the process of DNA replication during mitosis.
The idea of mutation is also important. There are 3 - 5 distinct mutations required before a normal cell becomes cancerous. And from this, it is necessary to understand the effect of mutations on the protein product the mutated gene codes for. So here, the mechanisms of transcription and translation are biological concepts the student must understand.
In our investigations, we have discovered that several of the apoptosis controlling proteins are on the cells' membranes, so we are looking at these structures in detail to find out exactly what happens here in both normal and cancerous cells.
Students also need to realise that the yeast cells we use in our investigations (Saccharomyces cerevisae) have important characteristics which make them useful to us. Yeast, like all organisms, recognise the universal genetic code: the DNA triplet code causes the same amino acid to be inserted into a protein, regardless of the species in which the protein is made. So when we put a human gene like BCL-2 into yeast the yeast cell treats the gene as if it were one of its own. But yeast are in fact rather simpler than animal and plant cells, and this is a big advantage to us. Every gene in yeast has now been identified in the yeast genome project, and we can see that there is no equivalent to the BCL-2 gene in the yeast genome. This means that, once we insert the gene, and get it to work, we can get a good idea of what it's doing by comparing the transgenic yeast to the untreated controls. The last reason that yeast is useful is that we can easily grow yeast cultures in the laboratory, obtaining billions of cells of our transgenic yeast in a very short time.
The surprising result that we found with the BCL-2 gene was that, whilst we thought that the gene seemed to prevent cell death in leucocytes, our yeast cells stopped dividing when they make the human BCL-2 protein.
Now we need to look at the whole question of what controls the cell cycle. Perhaps, it is necessary to have just the right amount of the protein of the BCL-2 gene. The yeast cells can't control all of the BCL-2 protein they make, and so they stop dividing. Cancer cells might use BCL-2 to help them to stop dividing when the immune system tries to kill them but then start dividing again when they're safe. It's an interesting puzzle.
The research group at WEHI are looking again at the human cancer cells, to understand the effect that BCL-2 has on cell division, and it does appear that BCL-2 can lead to cancer, at least partly because of its effect on the cell cycle. In this way the yeast cells were a good model of the cancer cells. If we can work out exactly how this gene and its protein act we might be on the way to getting the gene to give just the right amount of protein so that the unchecked cell division of a cancer can be controlled.
Interviewer: I now need to know something of the techniques used in your research. Can you tell me what techniques are important, and why they are important?
Dr Lithgow: A flow chart might make it easier to understand what we do:
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The BCL-2 gene is cut from the human chromosome number 14 using a restriction enzyme which, as you know, creates a length of DNA with sticky ends.
We use the same restriction enzyme to cut the circular plasmid DNA of the yeast. This gives a length of DNA with the same 'stickyness' as the BCL-2 gene's ends. By incubating the two together, in the presence of the enzyme DNA ligase, the ends all stick together, and we obtain a transgenic plasmid containiing the BCL-2 gene.
The transgenic plasmid is transferred into wild type yeast using lithium acetate to weaken the yeast cell membranes so that the plasmids enter the cells.
Since we do not get 100% uptake of the plasmids into the yeast we identify the transformed yeast by growing them on a minimal medium. On this selective minimal medium, only the yeast carrying the plasmid can grow.
We then allow the transgenic yeast to grow up in culture, and produce the protein that is coded for by the BCL-2 gene. The next task is to isolate the protein, using standard methods of cell fractionation. We use a neat trick of tagging the protein with an antibody which is luminiscent. This helps us to locate the protein in the cell fractions, because we can identify the antibody easily.
Once we have found the protein, we try to work out how it acts.
Interviewer: What do you see as the major biological implications of the work you are doing? For example; are genotypes or phenotypes being altered?, is a species survival potential increased?, will someone or something have a better quality of life?
Dr Lithgow: The yeast certainly have their genotypes and phenotypes altered when we insert the BCL-2 gene into them, but this isn't a 'major' implication. However, if we are able to find out exactly how this gene works, and we are then able to learn how to regulate its activity in cancer, both leukemia and other cancers, then the implications for patients will be extremely good.
Current cancer therapy, whether it is chemotherapy or radiation, is expensive. But worse than that, it often causes the patient to become extremely sick, not from the cancer but from the therapy. If we can develop a pinpoint treatment which works well, is inexpensive and makes the patient feel better, not worse, we will certainly have enhanced both the length and quality of those patients' lives.
Interviewer: There is often discussion or debate about issues associated with biotechnology. What is one such issue relating to your work? Can you outline the arguments of the opposing sides of the debate please?
Dr Lithgow: An issue which arises out of work such as this is what do we do with the information we are getting?'
As we find out about the structure, and activity, of genes which cause cancer it becomes easy to test for those genes in people. This raises all sorts of ethical questions:
These questions are similar to those being asked by people concerned about the Human Genome Project, and I think you will find lots of discussion about these issues on the Internet.
Interviewer: Can you suggest some reading material relevant to anything we have discussed about your work, its implications and issues associated with it?
Dr Lithgow: There have been some good articles written on this by Graeme O'Neill, one was written for La Trobe University and is a separate page on this Web site. The title is 'Yeast cells may yield clues to cell-suicide mechanism'. in fact, most of the Australian research in this area is done at the Walter and Eliza Hall, and O'Neill has written an article titled 'Physiological Cell Death' which you will find at the WEHI Internet site.
In addition to these, an Internet search using 'apoptosis' might find something useful.
Interviewer: Thank you for your time.
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