DISCLAIMER: This article is being kept online for historical purposes. Though accurate at last review, it is no longer being updated. The page may contain broken links or outdated information.
CRISPR-based immunity in prokaryotes
Westra, Edze R. Department of Agrotechnology and Food Sciences, Laboratory of Microbiology, Wageningen University, The Netherlands.
van der Oost, John Department of Agrotechnology and Food Sciences, Laboratory of Microbiology, Wageningen University, The Netherlands.
Brouns, Stan J. J. Department of Agrotechnology and Food Sciences, Laboratory of Microbiology, Wageningen University, The Netherlands.
- Mechanism of CRISPR defense
- Related Primary Literature
- Additional Reading
Recurrent viral attacks on prokaryotes have been a driving force for the evolution of immune mechanisms in these organisms that are crucial for their survival in the presence of these infectious elements. Viruses abuse bacteria to multiply, which often results in the death of the microbe. Therefore, bacteria have devised multiple defense strategies to resist phage predation. A relatively simple one is based on the elimination or modification of host proteins that are used by the virus as a surface receptor. Although this strategy prevents virus absorption and injection of the viral DNA, it may lead to an impaired fitness of the microbe. A second line of defense is formed by the well-studied restriction-modification system, which consists of an endonuclease enzyme and a methylase enzyme. While the host DNA is protected by methylation, invading DNA sequences without this methylation pattern are susceptible to cleavage by an endonuclease. However, the progeny of a single undetected virus particle will have a methylation pattern identical to the host and will no longer be recognized as an invader. Hence, an additional layer of defense against viral infection is based on clustered regularly interspaced short palindromic repeats (CRISPRs), which form the core of a sophisticated prokaryotic immune system that is both adaptive and inheritable.
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 10,000 highly qualified scientists and 46 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information