Editing of a chloroplast mRNA by creation of an initiation codon

Hoch, Brigitte; Maier, Rainer M.; Appel, Kurt; Igloi, Gabor L.; Kössel, Hans

doi:10.1038/353178a0

Cited by 329 publications

(200 citation statements)

References 17 publications

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“…The phenylalanine residue restored at editing site I is conserved even in the IRF170-encoded homolog of the more distantly related cyanobacterium Syn- echocystis. Previously, the ACG-to-ATG codon transition has been observed for the restoration of initiating methionine codons (3,4). With editing site II this transition is now also observed for the restoration of an internal methionine codon.…”

Section: Resultsmentioning

confidence: 99%

“…More recently, editing has been detected as an additional step of chloroplast mRNA maturation (3)(4)(5)(6)(7). This process was originally observed in mitochondrial transcripts of trypanosomes (8,9) but was subsequently also found in nuclear-encoded transcripts of mammals (10) and in mitochondrial transcripts of plants (11)(12)(13) and of the acellular slime mold Physarum (14).…”

Section: Introductionmentioning

confidence: 99%

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Complete RNA editing of unspliced and dicistronic transcripts of the intron-containing reading frame IRF170 from maize chloroplasts.

Ruf

Zeltz

Kössel

1994

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

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The maize plastome harbors within the rps4-rpsl4 gene cluster the reading frame IRF170, which is interrupted by two introns. Although the function of the encoded peptide of 170 amino acids is not known, the conservation of IRF170 homologs in other plastomes is a strong indication that IRF170 is a functional gene. Amplification and sequence analyses ofIRF170 specific cDNAs reveals two C-to-U editing events occurring within each of the first two exons. This situation allows an analysis of the temporal order between editing and splicing of a chloroplast transcript. By using intron-specific primer combinations, cDNAs derived from partially or even uuspliced IRF170 transcripts could be amplfied which in all cases showed complete editing. Complete editing was also observed with a cDNA derived from a transcript in which the proximal rps4 and the 5' half of IRF170-encoded sequences were still linked. This demonstrates that editing of the IRF170 transcript is an early processing step preceding both splicing and cleavage to monocistronic mRNA.The primary transcripts encoded by chloroplast protein genes are known to undergo a series of processing steps such as splicing, cleavage to monocistronic mRNAs, and trimming of terminal sequences (1, 2). More recently, editing has been detected as an additional step of chloroplast mRNA maturation (3-7). This process was originally observed in mitochondrial transcripts of trypanosomes (8, 9) but was subsequently also found in nuclear-encoded transcripts of mammals (10) and in mitochondrial transcripts of plants (11-13) and of the acellular slime mold Physarum (14). Depending on the different types of editing processes, the genetic information transmitted to the primary transcripts of the respective genes can be altered by nucleotide insertions and deletions (8,9,14) or by base substitutions (10-13). The editing events observed in chloroplast transcripts so far all result in C-to-U transitions, thereby restoring codons for conserved amino acid residues of the respective peptides (3-7).The reading frame designated IRF170 is subdivided by two introns and is well conserved within the rps4-rpsl4 gene cluster of the plastomes of higher plants (ref. 15; see Fig. 1), whereas a homologous reading frame without introns could be identified in the cyanobacterium Synechocystis (16). Although the function of the encoded peptide, consisting in maize of 170 amino acids, is not known, the absence of an IRF170 homolog in the plastome of the nonphotosynthetic parasitic plant Epifagus (17) as well as differences in the processing of IRF170 transcripts between amyloplasts and chloroplasts from maize (18) appears to suggest a function as a component of the photosynthetic apparatus. This supposition is further supported by the codon usage of IRF170-encoded mRNAs (15) and by the existence of a cyanobacterial IRF170 homolog (16).The existence of a large primary transcript which includes sequences of the flanking genes of the rps4-rpsl4 gene cluster and the presence of two introns in the IRF170-enco...

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Complete RNA editing of unspliced and dicistronic transcripts of the intron-containing reading frame IRF170 from maize chloroplasts.

Ruf

Zeltz

Kössel

1994

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

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“…Fax: (33) (56) 99-9057. from edited mRNAs [10]. RNA editing occurs also in some chloroplast transcripts although at a lesser extent than in mitochondria [11].…”

Section: Introductionmentioning

confidence: 99%

RNA editing in wheat mitochondria proceeds by a deamination mechanism

1995

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“…The insertional/deletional type of editing occurs in the kinetoplast of trypanosomes, where many mRNAs are edited by extensive addition or removal of uracil residues (2) and in some mitochondrial transcripts of Physarum polycephalum, where mainly C and, rarely, U and A residues are inserted (3,4). Substitutional editing occurs in mRNA transcripts of plant chloroplasts (5) and mitochondria (6)(7)(8) as well as in four mitochondrial tRNAs of Acanthamoeba (9), in three mitochondrial tRNAs of a land snail (10) and in one mitochondrial tRNA of potato and bean (11). Among mammals, substitutional editing has been described for the cytoplasmic mRNAs for apolipoprotein B (12) and a glutamate gated ion channel (13), as well as one cytoplasmic (14) and one mitochondrial tRNA (15).…”

Section: Introductionmentioning

confidence: 99%

C to U editing and modifications during the maturation of the mitochondrial tRNA^ASPin marsupials

1995

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In marsupial mitochondria, the nucleotide residue at the second position of the anticodon of the tRNA for aspartic acid is changed post-transcriptionally such that the translational machinery recognizes it as a uracil rather than the cytosine residue encoded in the gene. By postlabeling nucleotide analysis, we show here that the cytosine residue is converted to a conventional uracil residue in an RNA editing event that affects approximately half of the tRNA molecules under steady state conditions. Furthermore, we have identified three different tRNAASP species which all carry three pseudouridines and two methylations but have the anticodons GCC, GUC and QUC respectively, the latter representing a rare example of queuine incorporation into a mitochondrial tRNA. This allows us to describe a likely sequential order of modification of the tRNAASP, where methylations and conversions of uridines to pseudouridines precede the editing event, while the exchange of guanine by queuine takes place after the C to U editing event.

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Editing of a chloroplast mRNA by creation of an initiation codon

Cited by 329 publications

References 17 publications

Complete RNA editing of unspliced and dicistronic transcripts of the intron-containing reading frame IRF170 from maize chloroplasts.

Complete RNA editing of unspliced and dicistronic transcripts of the intron-containing reading frame IRF170 from maize chloroplasts.

RNA editing in wheat mitochondria proceeds by a deamination mechanism

C to U editing and modifications during the maturation of the mitochondrial tRNA^ASPin marsupials

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Editing of a chloroplast mRNA by creation of an initiation codon

Cited by 329 publications

References 17 publications

Complete RNA editing of unspliced and dicistronic transcripts of the intron-containing reading frame IRF170 from maize chloroplasts.

Complete RNA editing of unspliced and dicistronic transcripts of the intron-containing reading frame IRF170 from maize chloroplasts.

RNA editing in wheat mitochondria proceeds by a deamination mechanism

C to U editing and modifications during the maturation of the mitochondrial tRNAASPin marsupials

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C to U editing and modifications during the maturation of the mitochondrial tRNA^ASPin marsupials