Back to Merlin

Today I am starting another experiment designed to look at Merlin phosphorylation in deenervated schwann cells. It is a relatively easy experiment. I have four rats - two controls and two that will be treated with a PKA (protein kinase A) inhibitor. I will begin by making an incision in the right rear leg and cutting the sciatic nerve. I will then suture the wound up and let the rats recover for one week. Next Thursday, I will go back in, insert an osmotic pump that will release my PKA inhibitor over the cut nerve for 24 hours, and resuture the wound. On Friday, I will remove the pump, and take samples of the nerve proximal (closer to the midline of the body) to the cut and distal to the cut as well as taking the uncut contralateral nerve. Samples will be taken both for microscopy and protein analysis. The purpose to this experiment is to see if Merlin phosphorylation is controlled by PKA when a nerve is cut. We know that when a nerve is cut, the axon distal to the cut dies. This stimulates schwann cell proliferation. Our hypothesis is that PKA, at least in part, is responsible for this stimulation. Previous data have shown that PKA causes Merlin (a tumor supressor gene) to be phosphorylated. When Merlin is phosphorylated, it becomes inactive thereby allowing a cell to re-enter the cell cycle. We want to see we can prevent Merlin phosphorylation in the distal nerve section by treating with a PKA inhibitor. The first time we did the experiment there wasn't any difference between treated and control nerves. I think that was more a protein concentration problem when we loaded the gels but I could be wrong. The second time I did this experiment, the results were inconclusive. Hopefully the third time will be the charm.

I just finished the first round of surgeries and all of the rats are still alive. Hopefully they will be tomorrow also.