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Hi, I'm Cathy Burns.
My team and I study mobile DNAs.
Our DNA, the stuff that makes us who we are,
is organized like a line of sequence.
It's easy for me to show it to you, let's go to the toy box.
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Our DNA is made up of a linear sequence
of a high copy number repeats.
So they're very much like the building blocks of DNA.
I'm showing them like these blocks here, some are longer,
some are shorter.
They exist in many, many copies.
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There's also DNA sequence that is unique,
that exists only in one place in our DNA, like these gene
sequences that I'm showing with the colored blocks.
They are very important parts of our DNA.
Most of the repeated sequence we really do not understand well.
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Some people have called it the junk DNA in our genome,
and very few labs have studied it.
But I was fascinated to learn that these repetitive
sequences that sit around in such high quantity
are not just static fixed sequences in our genome.
They got here by making copies of themselves,
they are mobile elements.
And in fact, that activity is still continuing today.
These sequences are long and short.
The long elements encode for proteins and they're the engineers,
they're the masters of this continuing activity of mobile
DNAs in our genome.
So the coding sequence to make these proteins is part
of the line elements.
And normal cells keep line elements under really tight control, so
that you don't have a lot of these proteins produced.
When they're around, they can cause some instability in our genome.
They can create new repeats for our DNA.
So one of the proteins is a protein that's important as a carrier.
It carries a copy of the repeat sequence that will be copied.
And the other protein has a cutting activity
that finds a new site in our genome.
At essentially a random position in our genome,
this protein will make room for a new repeat sequence.
It will bring in the repeat sequence.
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It will actually copy the repeat into our DNA at a new location.
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So then, you can have consequences of that new insertion.
It could land in the middle of other repeat sequences and
have very little effect, but it could do something damaging.
It could interrupt one of the important sequences in our DNA.
My lab learned how to map new insertions of these mobile DNA
sequences.
And we're studying the presence of these proteins and
of those new insertions in cancer.
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As far as we know, this is a totally random process.
So it's kind of like playing a game of chance.
One of these new sequences can land in our DNA where it has no effect.
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Sometimes these sequences will land in the wrong place.
Just by chance,
they'll insert into a part of our DNA that does something critical.
Here, I'll show you an example of how they can insert and
really break the function of a surrounding gene.
So that new sequence now has come in and made an insertion of itself and
interrupted the normal gene function.
So that can cause human genetic disease,
it can also be a way that tumors damage their genes.
My lab studies insertions that land in these critical regions.
We think they maybe more common events than have been
recognized before, and we wanna understand the impact on those gene.
How a gene is affected by an insertion of a mobile DNA sequence
in a way that can cause human disease.
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