Abstract
Plastids send signals that regulate nuclear gene expression, thereby accomplished the assembly of photosynthetic apparatus. At present the plastid genome encodes fewer than 100 ORFs, and most of genes that were encoded by the bacterial ancestor have been moved to the host nuclear genome. This separation of genetic information necessitates the communication between plastids and the nucleus by plastid signals. However the molecular mechanisms underlying this inter-organelle signaling remains to be characterized.
To elucidate the signaling pathways from plastids to the nucleus, there is a significant evidence that the inhibition of protein import into plastids disrupts the expression of nuclear genes encoding plastid proteins. In ppi2 mutant lacking Toc159 protein import receptor, the mRNA levels of photosynthetic proteins are dramatically reduced. In this study, we performed global gene expression analysis of ppi2 mutant using SuperSAGE. We show that specific pathways regulate certain classes of genes were affected in ppi2 mutant.
