Iron‐dependent stability of the ferredoxin I transcripts from the cyanobacterial strains <i>Synechococcus</i> species PCC 7942 and <i>Anabaena</i> species PCC 7937

Bovy, Arnaud; Vrieze, Geert de; Lugones, Luis G.; Horssen, Peter van; Berg, C. van den; Borrias, Mies; Weisbeek, Peter

doi:10.1111/j.1365-2958.1993.tb01134.x

Cited by 36 publications

(26 citation statements)

References 65 publications

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“…Flavodoxin mRNA increases when iron is removed, but the ferredoxin mRNA level does not change. Ferredoxin protein, however, turns over rapidly in low iron medium (29).…”

Section: Discussionmentioning

confidence: 99%

Growth of the cyanobacterium Anabaena on molecular nitrogen: NifJ is required when iron is limited.

Bauer

Scappino

Haselkorn

1993

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

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“…Flavodoxin mRNA increases when iron is removed, but the ferredoxin mRNA level does not change. Ferredoxin protein, however, turns over rapidly in low iron medium (29).…”

Section: Discussionmentioning

confidence: 99%

Growth of the cyanobacterium Anabaena on molecular nitrogen: NifJ is required when iron is limited.

Bauer

Scappino

Haselkorn

1993

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

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“…Bovy et al (1993b) reported that the half life of Synechococcus ferredoxin I mRNA is greater in the presente of abundant iron. Both the 5' untranslated region and the first part of the coding region are required for this response (Bovy et al, 1993a), just as they are for the Fed-7 light response (Dickey et al, 1992b).…”

Section: Dlscusslonmentioning

confidence: 99%

Light modulation of ferredoxin mRNA abundance requires an open reading frame.

et al. 1994

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Ferredoxin I (Fed-l) mRNA abundance is modulated by an Interna1 light regulatory element that includes sequences both L'and 3'of the translational initiation site. To test the hypothesis that the light response mediated by this element might be coupled to translation, we transformed tobacco plants with gene constructs blocked in translational initiation or elongation. Here, we report that such mutations abollsh the light response ln vivo. A nonsense mutation could be rescued by restorlng the open reading frame with a different sequence, even when the new codon caused an amino acld substitution. Our data establlsh that the light response requires a translatable reading frame and thus pmvide strong circumstantial evidence for post-transcriptional modulation of Fed-1 mRNA levels. The Fed-1 system 1s presently the only higher plant example of a developmentally regulated change in mRNA abundance that requires translation of the affected mRNA. INTRODUCTIONFerredoxin I (Fed-7) is a nuclear gene encoding chloroplast ferredoxin in Pisum (Dobres et al., 1987; Dickey et al., 1992a). Like most genes encoding plastid proteins, Fed-7 is expressed more strongly in the light than in the dark. However, its light response differs in severa1 respects from those of other wellcharacterized light-responsive genes (Kaufman et al., 1986) and involves different molecular events (Thompson, 1988;Thompson and White, 1991;Neuhaus et al., 1993). Among the important differences is the fact that a major light response element in the pea Fed-7 gene is located within the transcription unit (Elliott et al., 1989), while other light-responsive genes are regulated mainly by upstream elements (Thompson and White, 1991;Kuhlemeier, 1992). We have recently shown that the Fed-7 interna1 light regulatory element (iLRE) is located within the 5' portion of the transcribed sequence and that it includes portions of both the leader and coding region (Dickey et ai., 1992b).The location of the Fed-7 iLRE within the transcribed portion of an intronless gene rules out transcriptional regulatory mechanisms that depend on upstream control elements and is consistent with models in which light modulates mRNA abundance by directly or indirectly affecting its rate of degradation. Direct observation of a light effect on mRNA stability has thus far been prevented by the fact that Ad-7 mRNA is stabilized when cellular RNA synthesis is inhibited by actinomycin-D (G.C. Allen, unpublished data). However, other data provide indirect support for a post-transcriptional model. In both tobacco andTo whom correspondence should be addressed.Arabidopsis, changes in mRNA abundance in light-grown versus dark-adapted plants occur in the absence of corresponding changes in the transcriptional activity of isolated nuclei (Dickey et ai., 1992b;Vorst et al., 1993), and the 5' portion of a pea Fed-7::GUS (P-glucuronidase) chimeric mRNA is stabilized in the light, whereas reporter sequences in the 3' portion of the transcript are degraded (Dickey et al., 1992b).Recent reports indicate that ...

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“…For example, the stabilities of ompA mRNA in Escherichia coli and aprE mRNA in Bacillus subtilis are regulated according to growth stage and growth rate, respectively (Emory and Belasco, 1990;Resnekov, 1990), endonucleolytic cleavage within the puf mRNA in Rhodobacter capsulatus is regulated by oxygen (Klug, 1991), and the ferredoxin I transcripts in Synechococcus are stabilized in the presence of iron (Bovy et al, 1993). Potential determinants of mRNA stability include both the 5Ј and 3Ј ends of the transcript, endonucleolytic sites within the transcript, and, in some cases, translation (reviewed in Brawerman, 1987;Cohen, 1995).…”

Section: Introductionmentioning

confidence: 99%

mRNA stability is regulated by a coding‐region element and the unique 5′ untranslated leader sequences of the three Synechococcus psbA transcripts

Kulkarni

Golden

1997

Molecular Microbiology

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SummaryThe psbAI and psbAIII transcripts in Synechococcus sp. strain PCC 7942 are subject to accelerated turnover when cells are exposed to high light intensities, but psbAII message stability is unaffected. We used a psbAI 'minigene' which has a part of the coding sequence removed as a reporter gene in order to identify the cis-acting elements of the transcript that determine stability. While engineering the minigene to optimally mimic the native gene, we identified a stabilizer element within the open reading frame, corresponding to the coding region for the first membrane span of the D1 protein, the presence of and translation through which was essential for normal psbA mRNA stability. We propose that this stabilizer is a site for ribosome pausing, and that accumulation of ribosomes on the transcript upstream of the pause site increases stability. To identify the elements that regulate the differential responses of the psbA transcripts to high-light growth, sequences from psbAII and psbAIII were substituted in the psbAI minigene reporter. The chimeric reporter transcripts established that the psbAI and psbAIII untranslated leaders determine the faster turnover of these messages. The untranslated leader regions of the psbA transcripts may regulate mRNA stability by modulating translation and thereby stability, or by recruiting RNA-binding proteins that affect mRNA turnover more directly.

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Iron‐dependent stability of the ferredoxin I transcripts from the cyanobacterial strains Synechococcus species PCC 7942 and Anabaena species PCC 7937

Cited by 36 publications

References 65 publications

Growth of the cyanobacterium Anabaena on molecular nitrogen: NifJ is required when iron is limited.

Growth of the cyanobacterium Anabaena on molecular nitrogen: NifJ is required when iron is limited.

Light modulation of ferredoxin mRNA abundance requires an open reading frame.

mRNA stability is regulated by a coding‐region element and the unique 5′ untranslated leader sequences of the three Synechococcus psbA transcripts

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