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Team:UCSF/Project/Background
From 2013.igem.org
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To selectively target and eliminate harmful bacteria, we are utilizing the CRISPRi system, a tool repurposed from a natural adaptive immunity system in bacteria (see diagram below). This tool is comprised of a catalytically dead Cas9 (dCas9) protein that complexes with guide RNAs (gRNA) complementary to the target bacteria’s DNA sequence. This complex binds to DNA complementary to the gRNA and prevents transcription, therefore repressing gene expression. </div> | To selectively target and eliminate harmful bacteria, we are utilizing the CRISPRi system, a tool repurposed from a natural adaptive immunity system in bacteria (see diagram below). This tool is comprised of a catalytically dead Cas9 (dCas9) protein that complexes with guide RNAs (gRNA) complementary to the target bacteria’s DNA sequence. This complex binds to DNA complementary to the gRNA and prevents transcription, therefore repressing gene expression. </div> | ||
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| - | <u>Solution to Problem 2:</u><br> | + | <b><FONT COLOR="#008000"><u>Solution to Problem 2:</u></font></b><br> |
As a means to introduce our CRISPRi system into a microbiome we’ve opted to utilize conjugation - a naturally occurring mechanism bacteria use to transfer DNA. By utilizing this mechanism, we are able to target specific strains of bacteria and affect gene expression. This will have a potential for future applications that require targeted cell death. </div> | As a means to introduce our CRISPRi system into a microbiome we’ve opted to utilize conjugation - a naturally occurring mechanism bacteria use to transfer DNA. By utilizing this mechanism, we are able to target specific strains of bacteria and affect gene expression. This will have a potential for future applications that require targeted cell death. </div> | ||
Revision as of 16:40, 23 September 2013
Rarely in nature do bacterial strains exist in isolation; they form complex microbial communities that interact with various organisms. In these communities, there are few ways to target specific strains effectively. The way people control bacteria is through antibiotics, which for the most part act indiscriminately. But often, problems stem from a single species that has invaded the microbial community; normal balanced microbiomes are not only harmless, but are often crucial and positively contribute to an environment. Because most therapies disrupt this balance, there is an obvious need for specific targeting of species in microbial communities.
At the beginning of this summer, we asked ourselves a question: “What could we introduce to a microbiome which would allow specific targeting and eventual elimination of harmful bacteria?” The difficulty faced with eliminating only one strain of bacteria in a microbiome is being able to
- Selectively target and eliminate harmful bacteria without negatively affecting other bacteria.
- Introduce a targeting system into a defined mixture of bacteria
Rather than using indiscriminate antibiotics and pesticides, we’ve designed a system that will solve these two problems.
Solution to Problem 1:
To selectively target and eliminate harmful bacteria, we are utilizing the CRISPRi system, a tool repurposed from a natural adaptive immunity system in bacteria (see diagram below). This tool is comprised of a catalytically dead Cas9 (dCas9) protein that complexes with guide RNAs (gRNA) complementary to the target bacteria’s DNA sequence. This complex binds to DNA complementary to the gRNA and prevents transcription, therefore repressing gene expression.
Solution to Problem 2:
As a means to introduce our CRISPRi system into a microbiome we’ve opted to utilize conjugation - a naturally occurring mechanism bacteria use to transfer DNA. By utilizing this mechanism, we are able to target specific strains of bacteria and affect gene expression. This will have a potential for future applications that require targeted cell death.
As a means to introduce our CRISPRi system into a microbiome we’ve opted to utilize conjugation - a naturally occurring mechanism bacteria use to transfer DNA. By utilizing this mechanism, we are able to target specific strains of bacteria and affect gene expression. This will have a potential for future applications that require targeted cell death.
