Out drinking with a few biologists, Jad finds out about something called CRISPR. No, it’s not a robot or the latest dating app, it’s a method for genetic manipulation that is rewriting the way we change DNA. Scientists say they’ll someday be able to use CRISPR to fight cancer and maybe even bring animals back from the dead. Or, pretty much do whatever you want. Jad and Robert delve into how CRISPR does what it does, and consider whether we should be worried about a future full of flying pigs, or the simple fact that scientists have now used CRISPR to tweak the genes of human embryos.
A lot of progress has been made in the past 30 years in understanding, preventing, and treating HIV (previous post), and now scientists have figured out a way to essentially delete the HIV virus from human DNA. To date, no cure exists for HIV/AIDS, but new developments from a group out of Temple University, published in PNAS, shows promise for suppressing viral gene expression and replication, and immunizing uninfected cells against HIV infection.
This finding is nicely summarized by the Daily Mail. The scientists have developed molecular tools to cut out the HIV gene from our genome. Here’s how it works:
Researchers based the two-part HIV-1 editor on a system that evolved as a bacterial defence mechanism to protect against infection.
When deployed, a combination of a DNA-snipping enzyme called a nuclease and a targeting strand of RNA called a guide RNA (gRNA) hunt down the viral genome and remove the HIV-1 DNA.
Dr Khalili’s lab engineered a 20-nucleotide strand of gRNA to target the HIV-1 DNA and paired it with a DNA-sniping enzyme called Cas9 and used to edit the human genome.
From there, the cell’s gene repair machinery takes over, soldering the loose ends of the genome back together – resulting in virus-free cells.
This next step is to develop the construct in order to conduct preclinical studies. There is still work to be done in fighting this disease, however, this new cas9 system for editing out HIV from the human genome is a step in the path towards finding a cure.
crestwind24 – This morning I am screening through many, many plates of worms. Usually this is very tedious, but today it is very exciting because I am looking for worms that have had their genomes edited using the CRISPR/Cas9 system!!! The CRISPR system allows scientists to make specific genetic changes in the actual genes of bacteria, cells, and animals. In the case of C. elegans, the CRISPR system allows scientists to target genes within the genome to mutate them, change them, delete them, or add things to them. It is extremely powerful, and hopefully I will find some worms that have the genetic edit that I designed!! Cross your fingers for me!
psgurel– Speaking of tedious, I am in the final steps of expressing and purifying protein. Purified protein is a requirement for a variety of biochemical experiments (like the kinetic assay or analytical ultracentrifugation I mentioned earlier). This whole process takes 5 days for the protein I’m expressing, where I’ve had to: grow and express my protein in E. Coli (E. Coli is typically used for protein expression because they grow very fast and yield a lot of protein), lyse the bacterial cells, harvest the protein through various methods of chromatography, concentrate my protein, then store it appropriately. Here I am posing with the FPLC, in the final step of purifying my protein. Looks like I got a good yield, yippee!