Egg P bodies protect maternal gene messages

Sometimes messages are held back to be read later, and in most cell types these delayed messages are stored and eventually marked for destruction in P bodies (processing bodies).

P bodies in worm egg cells, however, are message protectors, according to a paper by Boag et al. to be published in the Aug 11th issue of the Journal of Cell Biology. In a separate study Noble et al. report that worm eggs have different flavors of P bodies depending on developmental stage.

Boag et al. showed that P bodies in eggs lack a degradation protein called Pat1 that is present in the P bodies of other cells of the body. The eggs contain large numbers of maternally-derived gene messages (mRNAs), which won't be read until the egg is fertilized and the embryo starts to develop. By keeping their P bodies Pat1-free, eggs thus ensure their maternal messages stay safe until they are needed.

Noble et al. showed that eggs in fact have a whole range of specialized P bodies. They identified at least three types of P bodies arising at different stages of egg development, and a fourth type in embryos, each with a distinct set of proteins. Although Noble et al. weren't looking for Pat1 protein, they did find that two of the P body types that appear early in egg development lack a different degradation protein, DCAP-2, in line with the observations of Boag et al.

The different types of P bodies most likely have different functions, but they do appear to interact with one another, indicating that they might be exchanging mRNAs.