Recently a FaceBook friend of mine (who is not a scientist) shared a video from WIRED Science where the concept of CRISPR is explained at 5 Levels of Difficulty— for a 7 year old, a teenager, a college student, a grad student and a CRISPR expert.
First it was pretty amazing to me that my non-scientist friends are interested enough in learning about CRISPR to share this type of information—perhaps showing just how popular and exciting the method has become. People outside the scientific field are hearing a lot about it, and are curious to know more.
This video does a great job of explaining the technique for all its intended audiences. It also is a nice illustration of how to share information in an easily understandable format. Even with the 7 year old and 14 year old, the information is shared in a conversational way, with everyone involved contributing to sharing information about 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
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 “A Crash Course in CRISPR”
Summer, a much-looked forward to season. We typically pack in the activities and make the most of the daylight. We work hard and we play hard. This summer will be no exception, and at the BTC Institute, we are already getting set to host as many students as we can. We will see middle and high schoolers, K-12 teachers, college students, graduate students, college and university faculty and staff, and professionals in the biotech community under our roof at some point. You may want to join us too!
Our programs for advanced learners, geared toward the graduate student or biotech professional, offer much more than just a rigorous immersion in molecular biology theory and practice. Held at the BTC Institute at Promega Headquarters, they are taught by highly knowledgeable scientists, coming from both industry and academia. These instructors offer a wealth of information and share their expertise as well as life experiences with students. Informal discussions about career trajectories and access to industry are important added benefits to attending these off-campus workshops. Continue reading “Pack a Little Science into Your Summer with Advanced Courses from BTCI”
Microbial cells outnumber the cells of our own bodies approximately 10:1, these microbes that live on our skin and along the epithelial linings of our internal tubes make up our microbiota*, and they can have major effects on our health. Most of our microbiota are commensal organisms, living in harmony with our body, but if you suppress our immune system or greatly reduce their populations with large doses of antibiotics, and you will soon see the effects of disrupting our microbiota.
There is much interest in the microbiota that inhabit our bodies. For instance several studies have indicated that intestinal microbes can play a big part in obesity, with changes in the makeup of the microbiota being a major risk factor (1). But many of these organisms are hard to learn about—the ones that inhabit the deep folds of our gut thrive in moist, warm, anaerobic conditions with lots of specialized nutrients, conditions that are very hard to replicate in the laboratory. For that reason, we don’t know much about many of the microbes that are the most abundant within us.
The Human Microbiome Project begun in 2008 by the National Institutes of Health (2) seeks to understand human microbiota and their relationship to human health. To do this, the researchers leading the project took a metagenomic approach—using advanced DNA sequencing technologies to sequence the genomes of human microbiota and get a look at the human microbiome—without culturing the microbes.
But to truly understand their biology, and to perhaps exploit what we learn to enhance human health we need to be able to manipulate these organisms. In particular, biologists who are interested in synthetic biology would like to use these micro-organisms to monitor what is going on in our bodies, particularly our guts. What better monitor for these hard-to-access places than an organism that is already well adapted to live there? Continue reading “Manipulating Microbiota: A Synthetic Biology Exploration of the Gut”