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Have you ever wanted to selectively kill a subset of cells in your model system? Turns out that with light-inducible photosensitizers and a quick zap of the proper color light, you can do just that.  Photosensitizing dyes and proteins have been around for awhile (check out this review), but the Bruchez and Tsang labs recently developed a photosensitizer composed of the protein complex complex and the MG-2I-dL5** fluorogen that can be used to ablate cells in culture and in vivo.  Read on to learn more about this killer illumination technique!

Cas9 is the genome editing tool of choice for a number of model organisms: mammalian cells, yeast, drosophila, plants, worms, zebrafish, frogs, some bacteria; but not thermophilic (high heat loving) bacteria. Until recently the only available Cas9 proteins were isolated from mesophilic (medium heat loving) bacteria, such as Streptococcus pyogene’s SpCas9. These Cas9 proteins don’t work well at high temperatures, so to use them in thermophiles, bacteria must be grown at lower temps. This approach only works for facultative thermophiles (high OR medium heat loving), but not obligate thermophiles. However, the recent discovery of GeoCas9 by the Doudna lab has opened up the field of thermophilic bacteria to CRISPR/Cas9 genome editing.

Reproducible data are key to science, so scientists are used to repeating experiments to confirm their findings. But no scientist wants to repeat an experiment because of poor reagent quality. To make sure our AAV vectors are of the highest quality, we undertake a rigorous quality control process - read on to learn more!

In the second episode of our Hot Plasmids podcast series, you'll learn about new red fluorescent proteins, AAV tools for targeting the nervous system, and vectors for zebrafish engineering. You can find additional hot plasmids in our newsletter or on our hot plasmids webpage.

This post was contributed by guest blogger Iris Lindberg, Professor at the University of Maryland School of Medicine.

In the Lindberg Lab we often make cell lines that overexpress genes of interest; more recently we have also been using Addgene CRISPR vectors to generate cell lines with knockouts of specific genes. Many years ago, people in the laboratory became frustrated with using glass cloning rings to isolate colonies of antibiotic-resistant cells; during the time required to grease, place and fill a dozen cloning rings, the remainder of the colonies on the plate dried out and died. The alternative to cloning rings, dilution cloning into 96-well plates, is extremely time- and resource-consumptive, since only wells with one cell can give rise to single clones, and thus many plates must be examined for single clones and then handled. Additionally, many cell lines, especially the endocrine cell lines we most commonly work with, require extra serum to survive at low densities - adding to the expense of dilution cloning.