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Cellular and Molecular Biology

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Bipartite Phage Display

CELLS-$GWLBY

Filamentous phages can be used to anchor proteins or peptides of choice for multiple nanotechnology purposes. The use of two protein modules in close proximity produces a bipartite phage display which can be used to carry out two combined functions.

For example, one module can serve as a receptor or recognition unit for specific cells and another module can act as an enzyme, reporter molecule, signaling molecule, etc.

In which of the following experiments would “bipartite phage display” be applicable?

Select ALL that apply.

A

The outer membrane of Cell M is covered with glycoprotein T. Cell M is very susceptible to bacterial infection Y. This glycoprotein prevents Drug B delivery to the Cell M.

A phage (P1) has been engineered with DNA for 1) a receptor to glycoprotein T and 2) an enzyme that cleaves glycoprotein T. A culture of Cell M is infected with P1 and tested for uptake of Drug B.

B

Glioblastoma is a fast-growing lethal brain tumor that presents with glioma-initiating cells at the apex of the tumor. It is not known what specific and unique proteins or peptides are anchored in the outer membrane of these glioma-initiating cells.

Glioma-initiating cells were isolated from a tumor and injected into mice. A large library of phages with diverse peptide displays was injected into the mice and glioma cells were retrieved and analyzed for phages bound to the cells.

With this knowledge, phages were developed that display glioma binding peptides to specifically target glioma cells along with DNA for an enzyme known to be secreted and kill cells in close proximity.

C

A phage is engineered with DNA for a peptide sequence that is found in the intracellular region of ion channel H that permits calcium to enter the cell upon electrical stimulation. This ion channel is not found in K cells.

K cells are infected with the phage and loaded with a fluorescent calcium indicator which will fluoresce in the presence of calcium. Calcium is added to the medium, the cells are electrically stimulated and fluorescence inside the cells is measured.