Question

You have fused a mouse cell and a human cell and then treated the cell with specific antibodies that are covalently linked to fluorescent dyes (antibodies to mouse proteins – green; antibodies to human proteins – red). A.) What does the cell look like immediately after fusion? B.) Then you waited 40 minute and reexamined the cell, what does the cell look like now? C.) What is the cause of the change? What does it show?

Answer 1

Answer-

According to the given question-

We know that lipid molecule can diffuese within the plane of membrane. some proteins also move freely within the lipid bilayer while some are attached with the protein complex present one side of the membrane to other.

Two scientist David fyre and Micheal Edidin conducted a experiment in the year of 1970 to study two things at a time by using a technique -  

• fuse two cell of different species such as mouse and human cell
• labelling the surface of the cell with labelling dye.

They fuse both the cells and identified the human specific and mouse specific proteins present on the fused cell surface by tagging them with fluorescent antibodies.

mouse cell have mouse specific antibodies which are linked to green fluorescent dye such as fluorescein and human cell have human specific antibodies linked with red fluorescent dye such as rhodamine.

For fusion of the bothe the cells are done by treated with sendai virus which are responsible for fusion of euaryotic cell they may be of same species or of different species. after fusion the cells were exposed to green and red fluorescent antibodies and followed by observation under fluorescence microscopy. here they observe that the green fluorescent membrane protein found in the mouse was observed at the one half of this hybrid cell surface while the red fluorescent membrane protein from the human cell was present at the other half of the cell.

But after some times they starts to intermix and after 40 minutes they observe that the sepereta region was completely intermixed .

So based on that they predict that if the fluidity of membrane was decresed by decresing the temperature below the lipid bilayer transition temperature then intermixind cound be easily prevented and they concluded that the intermixing of fluorescent protein was happened due to lateral diffusion of both human as well as mouse proteins thhrough the lipid bilayer of plasma membrane.