Processing and degradation of chloroplast mRNA

The conversion of genetic information stored in DNA into a protein product proceeds through the obligatory intermediate of messenger RNA. The steady-s tate level of an mRNA is determined by its relative synthesis and degradati on rates, i.e., an interplay between transcriptional regulation and control of RNA stability. When the biological status of an organism requires that a gene product's abundance varies as a function of developmental stage, env ironmental factors or intracellular signals, increased or decreased RNA sta bility can be the determining factor. RNA stability and processing have lon g been known as important regulatory points in chloroplast gene expression. Here we summarize current knowledge and prospects relevant to these proces ses, emphasizing biochemical data. The extensive literature on nuclear muta tions affecting chloroplast RNA metabolism is reviewed in another article i n this volume (Barkan and Goldschmidt-Clermont, this issue). (C) 2000 Socie te francaise de biochimie et biologie moleculaire / Editions scientifiques et medicales Elsevier SAS.