Transgenic models of human disease Flashcards
learn it
What can a mutation in a single gene cause?
A disease
What is homologous recombination?
The swapping round of genetic material
What are transgenic models of human disease?
A mutant form of a gene (with a selection marker) is inserted into the nucleus of an embryonic stem cell (via a vector), and then allowed to grow into a whole animal
What is the role of the selection marker?
It disrupts the target gene, and enables selection of the mutant cells
What is the end goal of a transgenic model of human disease?
The host chromosome ends up with the mutated version of the gene that you are studying
Example of a property that a selection marker has?
It could provide resistance to a certain toxin
How would you select the mutant cells?
Use the specific property of the selection marker. E.g. if it provides immunity against a certain toxin, add the toxin to the group of cells that you have
What is done with the successfully identified mutant cells?
They are inserted into another blastocyst (not the one they came from) which is then transferred to a surrogate mother to develop
How can a particular gene be deleted only in a specific organ/tissue?
Cre-LoxP based methodology
Characteristic of loxP site?
They have two inverted repeats on either end, and a spacer sequence in the middle
Kind of example of loxP site?
ATAAGCTAAATA
What is the spacer sequence in ATAAGCTAAATA?
GCTA
What are the two inverted repeats in ATAAGCTAAATA?
ATAA and AATA
What happens when Cre-recombinase recognises two loxP sites?
It induces recombination between them, and the intervening sequence is deleted.
What would happen to a gene of interest if it was between two loxP sites, and Cre-recombinase was added?
Recombination between the loxP sites would be induced, and the gene would be deleted
What is a floxed allele
A gene that has had two loxP sited placed on either side of it
How is the gene of interest only deleted in a specific tissue/organ?
The Cre-recombinase promoter will only be activated in a specific tissue/organ (e.g. a heart specific promoter)
What would happen to a gene if the Cre-recombinase promoter was heart specific?
The Cre-recombinase would only be expressed in the heart, so the gene would only be deleted in the heart
Example of recombination into an animal cell?
Factor VIII is used as a haemophilia therapeutic protein, and the gene was transfected into hamster cells–> cells would then produce the factor VIII
Possible issue with using an animal cell to make a human protein?
The pattern of post-translational modification in the animal cell may be different to the pattern doen in humans
