Gene-specific trans-Regulatory Functions of Magnesium for Chloroplast mRNA Stability in Higher Plants

Horlitz, Martin; Klaff, Petra

doi:10.1074/jbc.m005622200

Cited by 34 publications

(28 citation statements)

References 58 publications

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“…CSP41a contains a single, broad specificity divalent metal binding site, but is optimally active in the presence of Mg 2+ ; the abundance of Mg 2+ in the chloroplast suggests that this is the physiological activator of CSP41a (Bollenbach and Stern 2003a). Interestingly, the K A,Mg 2+ for CSP41a is approximately 2 mM, a value that is within the physiological Mg 2+ concentration range, which varies from 0.5 mM in etiolated leaves to 2-3 mM in young light-grown leaves and 10 mM in mature green leaves (Horlitz and Klaff 2000;Ishijima et al 2003). Although CSP41b is known to catalyze a divalent metal-dependent reaction (Bollenbach and Stern, unpublished data), the biophysical parameters describing its interaction with Mg 2+ remain to be tested.…”

Section: Csp41mentioning

confidence: 92%

Processing, degradation, and polyadenylation of chloroplast transcripts

Bollenbach

Schuster

Portnoy

et al. 2007

Cell and Molecular Biology of Plastids

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In this chapter, we describe the major enzymes and characteristics of transcript 5' and 3' end maturation, and polyadenylation-stimulated degradation. The picture which emerges is that maturation and degradation share many prokaryotic features, vestiges of the chloroplast endosymbiont ancestor. The major exoribonucleases are well-defined, being polynucleotide phosphorylase and RNase II/R. The endonucleases include CSP41, with largely informatic evidence for homologs of prokaryotic RNases E, J, and III. The polyadenylation-stimulated degradation pathway, which occurs in most living systems, is a major player in chloroplast RNA degradation. We discuss known or potential roles for polynucleotide phosphorylase and a prokaryotic-type poly(A) polymerase. Finally, we discuss nuclear mutations that affect RNA maturation and degradation, defining genes that are likely or known to encode regulatory factors. Major questions for future research include how the ribonucleases, which are inherently nonspecific, interact with these specificity factors, and whether newly-discovered noncoding RNAs in the chloroplast play any role in RNA metabolism.

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Section: Csp41mentioning

confidence: 92%

Processing, degradation, and polyadenylation of chloroplast transcripts

Bollenbach

Schuster

Portnoy

et al. 2007

Cell and Molecular Biology of Plastids

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“…Group II introns fold into catalytically active conformations only in the presence of Mg2+ ions [226], and the concentration of free Mg2+ is dependent on chloroplast biogenesis and the activity of Mg2+ transporters in the chloroplast envelope [107]. Thus, regulation of Mg2+ availability could also limit splicing.…”

Section: Regulation Of Chloroplast Rna Splicingmentioning

confidence: 98%

Chloroplast Gene Expression—RNA Synthesis and Processing

Börner¹,

Zhelyazkova²,

Legen³

et al. 2014

Plastid Biology

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Both transcription and transcript processing are more complex in chloroplasts than in bacteria. Plastid genes are transcribed by a plastid-encoded RNA polymerase (PEP) and one (monocots) or two (dicots) nuclear-encoded RNA polymerase(s) (NEP). PEP is a bacterial-type multisubunit enzyme composed of core subunits (coded for by the plastid rpoA, B, C1 and C2 genes) and additional protein factors encoded in the nuclear genome. The nuclear genome of Arabidopsis contains six genes for sigma factors required by PEP for promoter recognition. NEP activity is represented by phage-type RNA polymerases. Factors supporting NEP activity have not been identified yet. NEP and PEP use different promoters. Both types of RNA polymerase are active in proplastids and all stages of chloroplast development. PEP is the dominating transcriptase in chloroplasts.Chloroplast RNA processing consists of hundreds of mostly independent events. In recent years, much progress has been made in identifying factors behind RNA splicing and RNA editing. Namely, pentatricopeptide repeat (PPR) proteins have come into focus as RNA binding proteins conferring specificity to individual processing events. Also, studies on chloroplast RNases have helped considerably to understand chloroplast RNA turnover. Such mechanistic insights are set in contrast to how little we know about the regulatory role of RNA processing in chloroplasts.Keywords Chloroplast transcription · Chloroplast RNA polymerase · Chloroplast promoter · Chloroplast RNA processing · Chloroplast RNA-binding proteins · PPR proteins · Chloroplast splicing · Chloroplast editing · Chloroplast RNA degradation · Chloroplast nucleases Abbreviations CRS2 Chloroplast RNA splicing 2 protein IR Inverted repeat NEP Nuclear-encoded plastid RNA polymerase

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“…Ca 2+ channel blockers prevented this increase (Ishijima et al, 2003). In spinach stromal Mg 2 § increased from 3 -4 mM to 8 -10 mM during development and was involved in stabilizing RNA (Horlitz and Klaff, 2000). So it is possible that chlorophyll formation is regulated to some extent by light induced increases in stromal Mg 2 § concentration, which increase the activity of the reductase.…”

Section: Glutamyl-trna Reductase: Enzyme Activitymentioning

confidence: 90%