Question

Please use this paper to answer both the sub section question in detail please. this paper is avialbale online so thier is no plagirism

http://genesdev.cshlp.org/content/9/7/783.full.pdf

Q. How did the use of the cactSu and cactΔPEST versions of cactus helped to demonstrate the existence of two types of degradation that control the levels of Cactus protein.

Answer 1

The two proteins CactSu and CactPest are involved in the degradation of cactus protein by two ways :

1. In presence of CactSu: the expression of more stable cactSu leads to the replacement of less stable cactus protein by degrading it.

It has been seen molecular detection that CactSu encodes a slightly truncated protein that appears to be more stable than wild-type Cactus. It was found that Cact su protein is smaller than the wild-type maternal protein. CactSu was expressed more than wild type even being equal embryos. Greater accumulation of Cact su protein confers its greater stability. it was observed in embryos that in equilibrium between the Dorsal/Cactus complex and free subunits, free Cactus protein tends to be a prone to degradation and newly synthesized Cactus could take its place in the complex. In this way we can say that in presence of CactSu the cactus protein gets degraded easily.

1. In presence of cactPest : There is blockage of signaling of cactus protein that is responsible for dorsalisation of the embryo. It causes the degradation of cactus protein. So its absence causes the stabilization of the Cactus protein.

In presence of CactusPest, deleting the PEST sequence stabilizes Cactus and strongly inhibits signaling.Absence of sequences immediately adjacent to the PEST region interferes with the destabilizing function of the PEST sequence. In this view, removing the PEST sequence entirely might result in an even more stable protein.