Latest Posts

All Posts

Cre-ating New Methods for Site-specific Recombination in Drosophila

Posted by Mary Gearing on May 12, 2015 9:32:10 AM

Cre-lox recombination is an incredibly useful molecular biology tool, but like any biological system, it has certain drawbacks. First, the efficiency of Cre recombination varies for different constructs and cell types. Second, Cre may induce recombination at pseudo- or cryptic loxP sites (estimated to occur at a frequency of 1.2 per megabase in mammals), leading to DNA damage and developmental aberrations. In multiple systems, Cre itself, without the presence of a floxed construct, may produce a phenotype. This problem is especially stark in Drosophila, where expression of Cre from the standard UAS/GAL4 system is toxic to proliferating cells. A Cre-estrogen receptor ligand binding domain-fusion can prevent this toxicity, but with the caveat of partial rather than complete recombination. If you’re looking to use site-specific recombination in Drosophila, read on to learn about new recombinases suitable for this system.

Gerald Rubin’s lab sought to make complex genome modifications in Drosophila using multiple recombinases. To make multiple, precise genome edits, the recombinases used must have high activity and specificity with low cross-reactivity, as well as low toxicity.

Read More >

Topics: Plasmid Technology, Cre-lox, Drosophila

Writing Scientific Manuscripts: Literature Searching, Reading, & Organizing

Posted by Guest Blogger on May 5, 2015 11:54:00 AM

This post was contributed by Johnna Roose. This post was originally published on Johnna's New Under The Sun Blog and is part of her larger tutorial series, A Beginner’s Guide to Writing Scientific Manuscripts.

Any scientific manuscript will require numerous other references to scientific literature to substantiate the facts upon which it builds. This means you have to become familiar with a body of literature related to the topic. Finding reliable references and sorting out what they mean is no small task. As a scientist, it is useful to make literature searching and reading a regular part of your routine. Set a goal to read a certain number of papers each week to keep up with the research in your area. When you are in ‘writing-mode’ for a grant or a scientific manuscript, the reading will likely be more intense, but it is a general good practice to keep up with the scientific literature a little bit at a time.

Read More >

Topics: Career, Science Communication

Evolution of Brainbow: Using Cre-lox for Multicolor Labeling of Neurons

Posted by Mary Gearing on Apr 24, 2015 10:39:00 AM

CRISPR-Cas9 genome editing may be the hot new way to manipulate gene expression, but other gene manipulation systems remain valuable to biology. Cre-lox recombination, discovered in the 1980s, is one of the most important ways to spatially and temporally control gene expression, especially in in vivo models, and new Cre-lox based technologies are still being developed today. In this post, I will highlight the evolution of the  Brainbow multicolor labeling system - a perfect example of the continued utility of Cre-lox. Check out our previous blog post, Plasmids 101: Cre-lox, if you need a quick primer on how Cre-lox recombination works.

Read More >

Topics: Plasmid Technology, Genome Engineering, Fluorescent Proteins

CRISPR Meets Synthetic Biology: A Conversation with MIT’s Christopher Voigt

Posted by Kendall Morgan on Apr 22, 2015 10:06:00 AM

As Christopher Voigt explains it, his lab at the Massachusetts Institute of Technology has been “working on new experimental and theoretical methods to push the scale of genetic engineering, with the ultimate objective of genome design.” It’s genetic engineering on a genomic scale, with the expectation for major advances in agriculture, materials, chemicals, and medicine.

As they’ve gone along, Voigt’s group has also been assembling the toolbox needed for anyone to begin considering genetic engineering projects in a very big way. In one of his latest papers, published in Molecular Systems Biology in November, Voigt and Alex Nielsen describe what’s possible when multi-input CRISPR/Cas genetic circuits are linked to the regulatory networks within E. coli host cells.

We talked with Voigt about this collision that’s taking place between CRISPR technology and synthetic biology, the tools he’s making available through Addgene, and where all of it is likely to lead us in the future. 

Read More >

Topics: Genome Engineering, Investigator Feature, Synthetic Biology, CRISPR

CRISPR 101: Non-Homologous End Joining

Posted by Guest Blogger on Apr 16, 2015 11:45:08 AM

This post was contributed by David Wyatt and Dale Ramsden, UNC at Chapel Hill.

One advantage to using the CRISPR/Cas system for genome engineering is the fact that Cas9 can be easily programmed to make a DNA double strand break (DSB) in the genome wherever the user chooses. After the initial cut, the next steps in the process involve repairing chromosomal DSBs. It is important to know that cells possess two major repair pathways  Non-Homologous End Joining (NHEJ) and Homology Directed Repair (HDR) – and how these pathways work, as this could be relevant when planning your experiment. This blog has previously considered the HDR pathway; below we’ll discuss NHEJ, and how it impacts what happens to Cas9-mediated DSBs in the genome.

Read More >

Topics: Genome Engineering, CRISPR, CRISPR 101

Blog Logo Vertical-01.png

Subscribe to Our Blog