If you hobnob around scientists, you might be increasingly hearing the mysterious acronym “CRISPR” being mentioned in conversation. CRISPR (pronounced like “KRIS-per”) sounds vaguely like part of a refrigerator, but it is in fact an object of much excitement for scientists studying DNA research and genetic engineering.
CRISPRs (Clustered Regulatory Interspaced Short Palindromic Repeats) originate in bacteria (as well as the microorganisms known as archaea). Although the general public is well aware that some bacteria are infectious, bacteria
can be infected, too, as they can face debilitating invasion from viruses called bacteriophages. It turns out that, like humans, bacteria have what perhaps can be called their own version of an immune system.
That’s where these CRISPRs enter the scene. CRISPRs contain a certain pattern of short repetitions of DNA base sequences separated by “spacer DNA.”
These repetitions have not received much notice in the past, but scientists have now realized that these spacer regions match the DNA that is also found in the infecting viruses. In effect, bacteria containing CRISPRs have stored this DNA as a way of remembering who their enemies are – and it gives them a way to fight back.
During bacteriophage attack, the matching bacterial DNA is transcribed to RNA, and this RNA forms part of a complex that homes in on and cuts away the corresponding bacteriophage DNA. While this is bad news for bacteriophages, the bacteria’s “immune system” is good news for researchers. Scientists have tinkered a little with the CRISPR system and refined it such that it is appropriate not just for targeting DNA in bacteriophages but DNA in just about any species you can think of – including humans.
It is hard to imagine that interest in CRISPR could be any more intense than it is. A seminal paper about CRISPR that came out in 2012 has already been cited by nearly 250 published articles. This number reflects the massive research innovation and interest in CRISPR technology. Work has included disrupting five genes in mouse embryonic stem cells at once, making mutant zebrafish, and knocking out genes in rice. Biotech companies interested in this genetic manipulation can find CRISPR services at Assay Depot.
Of course, this type of research always begs the question: Can this one day be beneficial for human health? Already, the potential to target 90% of human DNA sequences has been developed. The day may come when CRISPR is used to excise DNA with surgical precision in a patient. Much work needs to be done, including ensuring that the CRISPR system doesn’t also go after DNA sequences that the body needs. It seems a near certainty, however, that CRISPR will be the foundation of a mountain of intriguing research in the ensuing years.
1. Jinek, M. et al. 2012. A Programmable Dual-RNA-Guided DNA Endonuclease in Adaptive Bacterial Immunity. Science. 337(6096):816-821.