Gene-specific trans-regulatory functions of magnesium for chloroplast mRNA stability in higher plants.
In higher plant chloroplasts the accumulation of plastid-encoded mRNAs during leaf maturation is regulated via gene-specific mRNA stabilization. The half-lives of chloroplast RNAs are specifically affected by magnesium ions. psbA mRNA (D1 protein of photosystem II), rbcL mRNA (large subunit of ribulose-1,5-bisphosphate carboxylase), 16 S rRNA, and tRNA(His) gain stability at specific magnesium concentrations in an in vitro degradation system from spinach chloroplasts. Each RNA exhibits a typical magnesium concentration-dependent stabilization profile. It shows a cooperative response of the stability-regulated psbA mRNA and a saturation curve for the other RNAs. The concentration of free Mg(2+) rises during chloroplast development within a range sufficient to mediate gene-specific mRNA stabilization in vivo as observed in vitro. We suggest that magnesium ions are a trans-acting factor mediating differential mRNA stability.
Horlitz
M
M
Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, D-40225 Düsseldorf, Federal Republic of Germany.
Klaff
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D020121:5' Untranslated Regions; D015152:Blotting, Northern; D002412:Cations; D002736:Chloroplasts / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D017343:Genes, Plant; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism* / Q000494:pharmacology; D008954:Models, Biological; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics / Q000378:metabolism; D045332:Photosystem II Protein Complex; D018087:Plastids / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D018724:Spinacia oleracea / Q000737:chemistry* / Q000235:genetics*; D013997:Time Factors; D015533:Transcriptional Activation; D014466:Ultraviolet Rays
D020121:5' Untranslated Regions; D002412:Cations; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D012333:RNA, Messenger; D008274:Magnesium