CRISPR Flashcards
What does CRISPR stand for?
clustered regularly interspaced short palindromic repeats
What is crispr
a technique to loacte any place on any genome and make any alterations you would like to make.
Where was crispr found
it is a gene locus in many bacteria. derived from natural decent
what are other molecular tools from biological decent?
plasmids, viruses, restriction enzymes, DNA ligase, DNA polymerase
What is the innate defence in bacteria?
restriction enzymes which cut the viral genome at specific sites into pieces.
What prevents DNA of the attacked cell from being cut?
methylation
What is the adaptive defence in bacteria?
CRISPR
What does PAM stand for and what does it do?
protospacer adjacent motif. It is what it recognized byt the crispr complex. where the DNA is cut
What happens with CRISPR and the bacteria immune system?
when first expresed to a virus, the bacteria cell will chop up the viral DNA using a crispr complex and insert the into the CRISPR locus. The locus consists of short palindromic repeats, the viral fragments are inserted as nonrepetitive spacers between these repeats. When seen again, the CRISPR locus transcribes crRNA and a Cas gene is expressed and they find and cut the invading genome
What is the sgRNA?
single guide RNA. an engineered molecule that combines the functions of the crRNA and its assistants, the tracrRNA.
How is CRISPR used for us>
Can knock out genes we dont want. the repair system will no restore the original sequence. change the function of a gene on the basis of a donor template
How was it used in pigs?
they have a receptor called CD163 that plays an important immune role but also acts as a receptor for PRRS virus. They used crispr-cas9 to eliminate the pssrsv binding sequence but allowed for function of immune system still
How was it used in corn?
ARGOS8 is a gene in corn that has drought resistance but has a weak promoter site, so the CRSIPR system made it stronger
What functions are allowed if the Cas9 nuclease activity is turned off?
turn genes on or off, add epigenetic markers (-CH3 groups), and localize a given sequence in a cell .
What are the 4 coming possibilities?
editing:
1) cultured human cells for research purposes
2) somatic cells for medical reasons
3) germ-line cells or embryos to prevent transmission of diseases
4) editing cells for enhancements, not because of disease
