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The wonders of the molecular world, animated

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    I live in Utah,
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    a place known for having
    some of the most awe-inspiring
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    natural landscapes on this planet.
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    It's easy to be overwhelmed
    by these amazing views,
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    and to be really fascinated by these
    sometimes alien-looking formations.
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    As a scientist, I love
    observing the natural world.
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    But as a cell biologist,
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    I'm much more interested
    in understanding the natural world
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    at a much, much smaller scale.
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    I'm a molecular animator,
    and I work with other researchers
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    to create visualizations
    of molecules that are so small,
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    they're essentially invisible.
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    These molecules are smaller
    than the wavelength of light,
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    which means that we can
    never see them directly,
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    even with the best light microscopes.
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    So how do I create
    visualizations of things
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    that are so small we can't see them?
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    Scientists, like my collaborators,
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    can spend their entire
    professional careers
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    working to understand
    one molecular process.
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    To do this, they carry out
    a series of experiments
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    that each can tell us
    a small piece of the puzzle.
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    One kind of experiment
    can tell us about the protein shape,
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    while another can tell us
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    about what other proteins
    it might interact with,
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    and another can tell us
    about where it can be found in a cell.
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    And all of these bits of information
    can be used to come up with a hypothesis,
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    a story, essentially,
    of how a molecule might work.
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    My job is to take these ideas
    and turn them into an animation.
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    This can be tricky,
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    because it turns out that molecules
    can do some pretty crazy things.
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    But these animations
    can be incredibly useful for researchers
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    to communicate their ideas
    of how these molecules work.
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    They can also allow us
    to see the molecular world
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    through their eyes.
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    I'd like to show you some animations,
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    a brief tour of what I consider to be
    some of the natural wonders
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    of the molecular world.
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    First off, this is an immune cell.
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    These kinds of cells need to go
    crawling around in our bodies
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    in order to find invaders
    like pathogenic bacteria.
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    This movement is powered
    by one of my favorite proteins
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    called actin,
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    which is part of what's known
    as the cytoskeleton.
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    Unlike our skeletons,
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    actin filaments are constantly
    being built and taken apart.
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    The actin cytoskeleton plays
    incredibly important roles in our cells.
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    They allow them to change shape,
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    to move around, to adhere to surfaces
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    and also to gobble up bacteria.
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    Actin is also involved
    in a different kind of movement.
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    In our muscle cells, actin structures
    form these regular filaments
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    that look kind of like fabric.
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    When our muscles contract,
    these filaments are pulled together
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    and they go back
    to their original position
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    when our muscles relax.
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    Other parts of the cytoskeleton,
    in this case microtubules,
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    are responsible for long-range
    transportation.
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    They can be thought of
    as basically cellular highways
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    that are used to move things
    from one side of the cell to the other.
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    Unlike our roads,
    microtubules grow and shrink,
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    appearing when they're needed
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    and disappearing when their job is done.
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    The molecular version of semitrucks
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    are proteins aptly named motor proteins,
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    that can walk along microtubules,
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    dragging sometimes huge cargoes,
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    like organelles, behind them.
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    This particular motor protein
    is known as dynein,
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    and its known to be able
    to work together in groups
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    that almost look, at least to me,
    like a chariot of horses.
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    As you see, the cell is this incredibly
    changing, dynamic place,
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    where things are constantly
    being built and disassembled.
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    But some of these structures
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    are harder to take apart
    than others, though.
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    And special forces need to be brought in
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    in order to make sure that structures
    are taken apart in a timely manner.
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    That job is done in part
    by proteins like these.
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    These donut-shaped proteins,
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    of which there are many types in the cell,
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    all seem to act to rip apart structures
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    by basically pulling individual proteins
    through a central hole.
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    When these kinds of proteins
    don't work properly,
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    the types of proteins
    that are supposed to get taken apart
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    can sometimes stick together and aggregate
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    and that can give rise
    to terrible diseases, such as Alzheimer's.
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    And now let's take a look at the nucleus,
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    which houses our genome
    in the form of DNA.
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    In all of our cells,
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    our DNA is cared for and maintained
    by a diverse set of proteins.
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    DNA is wound around proteins
    called histones,
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    which enable cells to pack
    large amounts of DNA into our nucleus.
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    These machines
    are called chromatin remodelers,
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    and the way they work
    is that they basically scoot the DNA
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    around these histones
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    and they allow new pieces of DNA
    to become exposed.
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    This DNA can then be recognized
    by other machinery.
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    In this case, this large molecular machine
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    is looking for a segment of DNA
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    that tells it it's
    at the beginning of a gene.
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    Once it finds a segment,
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    it basically undergoes
    a series of shape changes
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    which enables it to bring in
    other machinery
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    that in turn allows a gene
    to get turned on or transcribed.
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    This has to be a very
    tightly regulated process,
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    because turning on the wrong gene
    at the wrong time
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    can have disastrous consequences.
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    Scientists are now able
    to use protein machines
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    to edit genomes.
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    I'm sure all of you have heard of CRISPR.
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    CRISPR takes advantage
    of a protein known as Cas9,
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    which can be engineered
    to recognize and cut
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    a very specific sequence of DNA.
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    In this example,
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    two Cas9 proteins are being used
    to excise a problematic piece of DNA.
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    For example, a part of a gene
    that may give rise to a disease.
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    Cellular machinery is then used
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    to basically glue two ends
    of the DNA back together.
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    As a molecular animator,
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    one of my biggest challenges
    is visualizing uncertainty.
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    All of the animations I've shown to you
    represent hypotheses,
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    how my collaborators think
    a process works,
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    based on the best information
    that they have.
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    But for a lot of molecular processes,
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    we're still really at the early stages
    of understanding things,
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    and there's a lot to learn.
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    The truth is
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    that these invisible molecular worlds
    are vast and largely unexplored.
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    To me, these molecular landscapes
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    are just as exciting to explore
    as a natural world
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    that's visible all around us.
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    Thank you.
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    (Applause)
Títol:
The wonders of the molecular world, animated
Speaker:
Janet Iwasa
Descripció:

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Video Language:
English
Team:
closed TED
Projecte:
TEDTalks
Duration:
06:05

English subtitles

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