Post-Transcriptional Control of Photosynthesis Gene Expression

Abstract

Oxygen tension and light intensity influence the formation of pigment protein complexes in facultatively photosynthetic bacteria. Multiple control mechanisms are required to regulate expression of photosynthesis genes in response to external factors and to guarantee the coordinated syntheses of components of the photosynthetic apparatus. Regulation ofexpression ofphotosynthesis genes is partly accomplished by variation of mRNA levels. Both the rate of synthesis and the rate of decay of mRNA are involved in determining these mRNA levels. Our current knowledge on the molecular mechanisms of stabilization and destabilization of mRNAs transcribed from photosynthesis genes will be summarized. Some experimental data suggest that photosynthesis genes are also regulated at later steps of gene expression. This chapter will address the 23S rRNA processing in Rhodobacter and its putative role in gene regulation. Other molecular mechanisms influencing the rate of translation or post-translational processes have not been investigated to date but evidence for their participation in regulation of photosynthesis genes is provided. Since regulation of bacterial photosynthesis genes has been studied most intensively in Rhodobacter capsulatus and Rhodobacter sphaeroides, this review will focus on the results obtained with these closely related bacterial species.