Digesting
worms
Catriona
Crombie, Wellcome
Trust Sanger Institute
United Kingdom
I
work as a postdoctoral researcher at The Wellcome Trust Sanger
Institute, which is based on the Wellcome Trust Genome Campus
in rural Cambridgeshire. The alarm goes off as usual at 7
o’clock. I have to stop and feed the horses on the
way into work. The field where they live is very
close to the Sanger Institute, so it doesn’t add much time
to my commute. Once there are five well-fed and happy horses,
I get changed and head into work.
The first thing I do on arrival is to check and answer my
e-mail. I then write a plan of the tasks I need to do in the
lab today. I work in a lab interested in mapping cellular
signalling network through large scale systematic methods.
We use a nematode worm, Caenorhabditis Elegans,
as a model system to do this. My project is specifically interested
in some of the genes that are involved in cancer development.
I have carried out a number of genetic screens in the worm.
Using RNAi -- a method of specifically knocking down the expression
of any gene – we can do this for nearly all the genes in the
worm genome. I have identified a number of candidate genes,
and now I am trying to back up what we have done by replicating
the results in worms that carry mutations in the genes I am
interested in. I am trying to cross two strains of worm to
give worms that carry mutations in both the genes I am investigating.
I need a way of telling whether or not a worm has the mutations
that I seek. So I do a PCR – a method of making lots of copies
of a specific bit of DNA -- for one of the genes I want to
see which worms carry the mutation. Before I can do the PCR
reaction, I need the DNA from the worm. I
get this by digesting the worm away with an enzyme called
proteinase K.
I set this reaction up and leave the
worms to digest over lunchtime.
Wednesdays are Rugby training day. I play in the Genome Campus
Touch Rugby Team, and we train every Wednesday at lunchtime.
When I get back from training, the Proteinase K digestion
is complete, and I am left with no worms, just their DNA.
I then use this DNA to set up the PCR reaction.
We have a number of groups that all work with ‘model organisms,’
such as yeast and fish. So every week, we have a meeting attended
by all those who work with a model organism. I leave the reaction
that I started while I go to the meeting. Today, two people
are presenting their work. Andy from our lab talks about some
his efforts with microarrays. Richard from one of the zebrafish
labs talked about work with a fish model for muscular
dystrophy.
When the meeting is over, I go back to pour a gel. To see
the DNA from my PCR reaction, I separate out pieces of DNA
of different sizes in a gel. I then visualise them with a
chemical called ethidium bromide, which binds to DNA and fluoresces
under UV light. I set my gel up and leave it to run.
We have recently had two new lab groups move in to share the
space that we already share with four other groups. So, while
my gel is running, I chat to people from the other groups
to negotiate on how we can streamline use of the equipment
we have and the waste that we generate. I also check that
all my stock of worms have enough food and are growing
happily. I then look at the result of the PCR reaction
on my gel and take a picture of it. It looks good. I write
up what I have done today and go home.
I have always had an interest in how things work,
whether they were biological or mechanical
things. At school, I found that I did well at the scientific
subjects and maths. So studying science at degree level seemed
a very natural route to take. Later in my degree program,
I specialised in biochemistry. In doing my own research project,
I discovered that finding the answers to the questions you
have set out to investigate is very rewarding. I still have
a real passion for the science that I do and very much enjoy
sharing that with others.
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