Question

1) You have cloned a putative extracellular ligand and wish to identify a receptor for this ligand. Outline a technique you could use to isolate such a receptor, being sure to mention how you would determine the identity of the receptor.

2) You would like to perform a dominant second-site modifier screen in Drosophila. You generate a rough eye phenotype by misexpressing your gene of interest in a UAS construct using an eye-specific Gal4 driver.  How would you select for genes that are downstream effectors in the pathway?  Once you identify such a modifier, what are 2 distinct non-genetic experiments you would do next to further address the interaction between the modifier and the product of the original gene?

Help , please!

Answer 1

​​​​​Answer 1:-

1. The answer to this query is radiologists binding assay. This includes use of a radioactive isotopes which can be bound to a ligand in order to study the assay for binding to specific receptor of choice.
2. The radioactive signal can be detected and can be used to determine the affinity and strength of interaction apart from determining density and studying ligand-receptor interaction.
3. The ligand is introduced into an assay in order to measure the interaction. Depending on the kinetics and associated reactions, a receptor can be specified for that ligand.
4. This method can be coupled with X-ray crystallography in order to study the 3D structures of proteins of interest which may include the G-protein coupled receptors and the ligands in order to study the compactiveness of binding.
5. BLAST analysis coupled with amino acid sequencing can be used to identify a particular receptor for that particular ligand.