REGULATION AND EXPRESSION OF GENES FOR CHLOROPLAST PROTEINS

Abstract The biosynthesis and function of a chloroplast are controlled by genes located in two genomes, that in the nucleus of the photosynthetic cell and that in the organelle itself. This dual location raises many questions as to how the nuclear and chi genes which code chl-specific ribonucleic acids and proteins are regulated and coordinated to produce a functioning organelle. Though much remains to be answered, the overall pattern of expression of genes coding chi proteins is becoming clear. This review considers the expression of the genes coding two chi proteins, i.e. the light-harvesting chlorophyll a/b protein which is coded in the nucleus, and the enzyme ribulose-1,5- bisphosphate carboxylase which is composed of two subunits, one of which is coded in the nucleus and the other in the chloroplast. All levels of expression of these genes are considered from their structure and transcription to the final assembly and integration of their functional protein products into the appropriate compartment o...