In a Perfect World, Bacteria Wins

iGEM 2018 from aboveLast month, several of my Promega colleagues and I attended the 2018 iGEM Giant Jamboree in Boston, MA. This annual event is the culmination of the International Genetically Engineered Machines competition, in which 350+ teams of high school, undergraduate and graduate students use synthetic biology to solve a problem they see in the world.

The iGEM Giant Jamboree is the closest I have ever come to a scientific utopia. For four days, several thousand students from 45 countries come together to share their experiences and discuss ways that science can change the world. They present impressive projects with real-world applications including human diagnostics and alternative energy. Collaboration and open science are among the core tenets of iGEM, and it’s not unusual to see three or more countries represented on the Collaborators slide at the end of a presentation. Each project also contains a public engagement component, which many teams fulfill with educational programs or partnerships with underrepresented communities. Continue reading

Hey, iGEMers! We’re talking to you!

The 2018 iGEM Giant Jamboree is upon us! This Wednesday, October 24th, thousands of you will flood into Boston, weighed down by posters and presentation materials, but energized by the excitement of a non-stop science-packed conference. Promega will also be attending, with a booth full of helpful giveaways and staff standing by to answer all your questions about science, Promega or future careers. As you make your final plans for the Jamboree, here are a few helpful tips for making the most of this incredible opportunity.

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iGEM: Building Living Machines

Life forms are often compared to machines, whether you are referring to a single cell or a complex organism. This concept is the basis for the International Genetically Engineered Machine (iGEM) Competition. Each year, high school and university students around the world assemble teams that create genetically engineered systems. In addition to the building work, teams document their process and progress through wikis that are assessed by judges at the end of the competition.

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Some members of iGEM 2016 Team Duesseldorf.

In order to synthesize these living machines, iGEM teams use standard biological parts called biobricks—each biobrick is a sequence of DNA encoding a particular biological function. Teams receive a kit of standard biobricks and work over the summer to build and test biological systems in living cells. These basic units are put together to make more complex parts which can then be grouped together to make “devices” that can function within living cells. Continue reading

A Crash Course in CRISPR

CRISPR is a hot topic right now, and rightly so—it is revolutionizing research that relies on editing genes. But what exactly is CRISPR? How does it work? Why is everyone so interested in using it? Today’s blog is a beginner’s guide on how CRISPR works with an overview of some new applications of this technology for those familiar with CRISPR.

Introduction to CRISPR/Cas9

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Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) were discovered in 1987, but it took 30 years before scientists identified their function. CRISPRs are a special kind of repeating DNA sequence that bacteria have as part of their “immune” system against invading nucleic acids from viruses and other bacteria. Over time, the genetic material from these invaders can be incorporated into the bacterial genome as a CRISPR and used to target specific sequences found in foreign genomes.

CRISPRs are part of a system within a bacterium that requires a nuclease (e.g. Cas9), a single guide RNA (sgRNA) and a tracrRNA. The tracrRNA recruits Cas9, while sgRNA binds to Cas9 and guides it to the corresponding DNA sequence of the invading genome. Cas9 then cuts the DNA, creating a double-stranded break that disables its function. Bacteria use a Protospacer Adjacent Motif, or PAM, sequence near the target sequence to distinguish between self and non-self and protect their own DNA.

While this system is an effective method of protection for bacteria, CRISPR/Cas9 has been manipulated in order to perform gene editing in a lab (click here for a video about CRISPR). First, the tracrRNA and sgRNA are combined into a single molecule. Then the sequence of the guide portion of this RNA is changed to match the target sequence. Using this engineered sgRNA along with Cas9 will result in a double-stranded break (DSB) in the target DNA sequence, provided the target sequence is adjacent to a compatible PAM sequence. Continue reading