Projektbeschreibung
Adaptive Immunität bei Bakterien
Um in einer feindlichen Umgebung unter ständigen Angriffen von Viren zu überleben, haben Mikroben ein adaptives antivirales System namens CRISPR-Cas entwickelt. Das System baut die DNS-Sequenzen des Eindringlings in einen Speicherort (CRISPR) ein und bildet aus diesem Ort Leit-RNS, gefolgt vom Abbau der eindringenden Ziel-DNS durch CRISPR-RNS-geführte Proteinkomplexe. Die Punktmutationen in der Zielregion der DNS des Eindringlings werden vom System erkannt, indem neue Gedächtnissequenzen gegen denselben Eindringling über einen Priming-Prozess integriert werden. Das vom Europäischen Forschungsrat finanzierte Projekt REMEMBER zielt darauf ab, den Mechanismus der Gedächtnisbildung bei CRISPR gegen mutierte Viren, die Bakterien infizieren, aufzudecken. In der Studie wird die Hypothese getestet, dass perfekt passende und degenerierte Targets den gleichzeitigen Abbau der Virus-DNS und die Aktualisierung des Gedächtnisses auslösen.
Ziel
Microbes in natural ecosystems are under constant evolutionary pressure from viruses. To survive in this hostile environment microbes have evolved an adaptive immune system called CRISPR-Cas. The immune system is based on incorporation of invader DNA sequences in a memory locus (CRISPR), the formation of guide RNAs from this locus, and the degradation of invading target DNA using CRISPR RNA-guided protein complexes. Invaders escape immunity by making point mutations in the targeted region of their DNA, but hosts quickly restore immunity by integrating new memory sequences against the same invader in a process called priming. Recently, I have made the remarkable discovery that hosts mount a primed immune response even when facing heavily mutated invaders. This implies that the memory of the CRISPR-Cas system not only functions in the short term against relatively recent threats, but also remembers a range of revisiting old foes in the long term, providing a huge evolutionary benefit for the host in the arms race with their invaders.
This proposal sets out to determine the mechanism of the enigmatic process of primed memory formation against heavily mutated invaders. Using a combination of genetic, biochemical and structural approaches, including state-of-the-art single molecule imaging of CRISPR immunity in living Escherichia coli cells, I will investigate the driving hypothesis that perfectly matching and degenerate targets are differentially recognized, and trigger either target DNA degradation or priming. Moreover, I will test the supposition that degenerate priming is a universal phenomenon among different CRISPR-Cas types. If this is the case, degenerate priming will impair the use of viruses as therapeutic agents to treat antibiotic resistant bacterial infections. To prevent CRISPR resistance I propose to screen for organic molecules that inhibit the formation of CRISPR resistance. These molecules can be co-administered with viruses to potentiate treatments.
Wissenschaftliches Gebiet
- medical and health sciencesmedical biotechnologygenetic engineeringgene therapy
- natural sciencesbiological sciencesmicrobiologybacteriology
- natural sciencesbiological sciencesmicrobiologyvirology
- natural sciencesbiological sciencesgeneticsDNA
- medical and health sciencesbasic medicinepharmacology and pharmacydrug resistanceantibiotic resistance
Programm/Programme
Thema/Themen
Finanzierungsplan
ERC-STG - Starting GrantGastgebende Einrichtung
2628 CN Delft
Niederlande