Question

Conditional alleles are commonly used by geneticists to control when (temporal) and where (spatial) specific traits are expressed. In this question, you should outline a strategy utilizing the genetic tools that we have discussed during class. It might be simpler to draw a diagram of the engineered loci. Include all the components that are required for the experiment to be successful. (Tools: Cre-Lox and FLP-FRT recombination, forgot to previously list the tools)

A) What strategy could you use to switch off gene expression in liver cells?

B) Why is a conditional allele valuable for scientists when studying gene function?

C) What strategy could you use to switch on gene expression in liver cells in an adult mouse?

Answer 1

A)  A technique, Conditional gene knockout is used to delete a particular gene in a specific tissue like liver. This technique is used to know about the function of individual genes in an organisms. It is different from traditional gene knockout in a manner that it aims particular genes at correct times. we can reduce the side effects originate from traditional gene knockout by using the conditional gene knockout technique.Due to mutation in traditional gene knockout, embryonic can occur, and due to this scientists are unable to study the gene in adults. Cre-lox recombination system is a technique that is most used to create a conditional knockout. An enzyme Cre recombinase particularly recognizes two recombination sites loci within DNA that leads to the recombination between them. Exchange of information between 2 strands of DNA takes place during recombination. This recombination will result in a gene deletion or gene inversion between the two recombination loci sites, that depends on their orientation. To inactivate it, an entire gene can be removed.

C) tetracycline transactivator system is an appropriate tool for regulating expression of transgene. This alter the pathways that control the tetracycline resistance gene expression in E. coli. This gene is basically repressed by repressor protein of tetracycline (tetR) that binds to operator sequence of tetracycline (tetO), causes the gene silencing. tetracycline relieved the repression, which avidly binds tetR.

B) study of conditional allele is valuable for scientists because they can study the progress of many genetic diseases at the molecular level like cancer, alzhimers disease, etc.