Transcription, Processing and Editing in Plant Mitochondria

Journal of Biological Chemistry

1995

To elucidate the mechanism involved in the transcription initiation process in mitochondria of dicotyledonous plants, an in vitro transcription system was established for pea (Pisum sativum L.). The partially purified mitochondrial protein extract initiates transcription on homologous pea templates as well as on heterologous mitochondrial DNA from other dicot plant species. In vitro transcription begins within the nonanucleotide 5-

supporting

confidence: 60%

A Novel Pea Mitochondrial in Vitro Transcription System Recognizes Homologous and Heterologous mRNA and tRNA Promoters

Binder

Hatzack

Journal of Biological Chemistry

1995

“…This dispersed arrangement of genes in plant mitochondria has prompted speculations about the number and the nature of promoters required to transcribe the essential genomic information in plant mitochondria (8,18). Investigations by in vitro capping and in vitro transcription have indeed revealed the presence of several distinct promoter regions for rRNA and protein coding genes (18,19).…”

Section: Introductionmentioning

confidence: 99%

A tRNA gene transcription initiation site is similar to mRNA and rRNA promoters in plant mitochondria

Binder

1993

Nucl Acids Res

INTRODUCTIONIn all genetic systems structural RNAs are subject to extensive, specific expressional control. Particularly rRNAs and tRNAs are required in quantities exceeding the abundance of any mRNA molecule species. To achieve and ensure the necessary supply of rRNAs and tRNAs specific modes of transcription have become established in many genetic systems. In the nucleus of eukaryotes for example, tRNA and the 5S rRNA genes are transcribed by a specific RNA polymerase (RNA-Polymerase M) from gene internal promoters (1), while a high rate of transcription of the other rRNA genes is provided by amplification of these genomic sequences (2).In the compact organellar systems of plastids and mitochondria similar strategies are used to meet the requirements for abundant RNA molecules. In plastids rRNA genes are duplicated and evidence for an additional RNA-polymerase (and/or its respective

“…In both organelles specific cytidines of the primary transcripts are altered to uridines in the mature mRNAs. Only a few instances of editing have been found in chloroplasts (4)(5)(6), whereas numerous editing events have been documented in mitochondria of higher plants for almost all mRNAs investigated (7)(8)(9)(10)(11). In the more thoroughly investigated higher plant species, all of the open reading frames encoding conserved functional polypeptides appear to be edited to some extent and the total number of editing sites documented amounts to 294 in wheat (11) and to >400 in Oenothera (10).…”

mentioning

confidence: 98%

“…Mitochondrial RNA editing has been reported in a number of angiosperm species, including the monocots wheat and maize and the dicots Oenothera, Sorghum, Petunia, Daucus, and Arabidopsis (7)(8)(9)(10)(11). The observation of analogous RNA editing in both monocots and dicots suggests that the origin of this process predates the divergence of the two lineages and is generally present in angiosperms.…”

mentioning

confidence: 99%

Evidence for RNA editing in mitochondria of all major groups of land plants except the Bryophyta.

Hiesel

Combettes

Proc. Natl. Acad. Sci. U.S.A.

1994

109

RNA editing has been documented in mitochondria of higher plants, notably dicots and monocots. To determine the distribution of mitochondrial RNA editing in the plant kingdom, we have now undertaken a survey of evolutionarily distant plants. RNA editing occurs in all major groups of land plants except the Bryophyta, suggesting that this process is an ancient trait that was established before the radiation of kormophyte plants. No editing is observed in representatives of the green algae, suggesting that editing arose in early land plants after the split of the Bryophyta or has been lost selectively in both algae and mosses. In ferns several U -* C changes are observed, one of which eliminates a genomically encoded UAA termination codon and creates a functional open reading frame.RNA editing has been observed in mitochondria and chloroplasts of angiosperm plants belonging to the Dicotyledonae and Monocotyledonae (1-3). In both organelles specific cytidines of the primary transcripts are altered to uridines in the mature mRNAs. Only a few instances of editing have been found in chloroplasts (4-6), whereas numerous editing events have been documented in mitochondria of higher plants for almost all mRNAs investigated (7-11). In the more thoroughly investigated higher plant species, all of the open reading frames encoding conserved functional polypeptides appear to be edited to some extent and the total number of editing sites documented amounts to 294 in wheat (11) and to >400 in Oenothera (10). The observed effect ofthis extensive editing on the encoded polypeptide sequences suggests that many of the higher plant mitochondrial genes would not encode functionally competent products without appropriate "correction" by RNA editing.Mitochondrial RNA editing has been reported in a number of angiosperm species, including the monocots wheat and maize and the dicots Oenothera, Sorghum, Petunia, Daucus, and Arabidopsis (7-11). The observation of analogous RNA editing in both monocots and dicots suggests that the origin of this process predates the divergence of the two lineages and is generally present in angiosperms. Recently, RNA editing has also been described in the gymnosperm Thuja (12). However, none of the plant species presumed to be closer to the evolutionary origin of flowering plants has been investigated. The only mitochondrial sequence data available allowing any inference about the need of RNA editing in nonflowering plants are from two bryophytes.Analysis of protein sequences deduced from the complete genomic nucleotide sequence of the liverwort Marchantia polymorpha (13) and comparison of several cDNA and genomic DNA sequences (14) did not show any evidence of RNA editing. Genomic sequence analysis of a mitochondrial gene in the moss Physcomitrella patens (15) allows a similar deduction, suggesting that RNA editing might not occur in mitochondria of the two bryophytes.The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "adve...