The paper:
R. Barrangou et al., "CRISPR provides acquired resistance against viruses in prokaryotes," Science, 315:1709–12, 2007. (Cited in 66 papers)
The finding:
Using the bacterium Streptococcus thermophilis, a team led by Philippe Horvath at the Danish food ingredient company Danisco, integrated bacteriophage sequences into "clustered regularly interspersed short palindromic repeat" (CRISPR) regions to generate phage-resistant bacterial strains. "They directly confirmed the prediction," says Eugene Koonin, a computational biologist at the US National Center for Biotechnology Information.
The follow-up:
Koonin, together with John van der Oost at Wageningen University in the Netherlands, reconstituted the CRISPR phenomenon in Escherichia coli, and showed that a complex of CRISPR-associated (Cas) proteins cleaves a CRISPR RNA precursor, leaving only the virus-derived sequence, which then interferes with phage proliferation (Science, 5891:960–4, 2008).
The application:
Danisco is exploiting the CRISPR mechanism to improve the antiviral immunity...
The extension:
Erik Sontheimer and Luciano Marraffini of Northwestern University showed that CRISPR sequences can impede the spread of antibiotic resistance by blocking the transfer of plasmids between Stapholococcus species (Science, 322:1843–5, 2008).
Sensitivity to phage (measured by plaque efficiency)* |
Wild-type Streptococcus: 1.0 |
Wild-type with one phage spacer: 1.8 x 10-5 |
Wild-type with two phage spacers: <10-7 |
*J Bacteriol, 190:1390-1400, 2008 |