Nucleus-encoded plastid sigma factor SIG3 transcribes specifically the psb N gene in plastids

Zghidi, Wafa; Merendino, Livia; Cottet, Annick; Mache, Régis; Lerbs-Mache, Silva

doi:10.1093/nar/gkl1067

Cited by 79 publications

(84 citation statements)

References 52 publications

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“…Compared with C 3 species, it appears that for two of these trans-factors, their targets may have diverged. For example, in Arabidopsis, SIG3 regulates PsbN (Zghidi et al, 2007), and while SIG3 transcripts in S. viridis and maize were both BS specific, we did not detect any cell specificity of PsbN transcripts. Furthermore, ORRM1 is involved in editing transcripts encoding the NDH complex of Arabidopsis (Sun et al, 2013).…”

Section: Regulators Underlying Patterns Of Convergence In C 4 M and Bcontrasting

confidence: 66%

Evolutionary Convergence of Cell-Specific Gene Expression in Independent Lineages of C4 Grasses

et al. 2014

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Leaves of almost all C 4 lineages separate the reactions of photosynthesis into the mesophyll (M) and bundle sheath (BS). The extent to which messenger RNA profiles of M and BS cells from independent C 4 lineages resemble each other is not known. To address this, we conducted deep sequencing of RNA isolated from the M and BS of Setaria viridis and compared these data with publicly available information from maize (Zea mays). This revealed a high correlation (r = 0.89) between the relative abundance of transcripts encoding proteins of the core C 4 pathway in M and BS cells in these species, indicating significant convergence in transcript accumulation in these evolutionarily independent C 4 lineages. We also found that the vast majority of genes encoding proteins of the C 4 cycle in S. viridis are syntenic to homologs used by maize. In both lineages, 122 and 212 homologous transcription factors were preferentially expressed in the M and BS, respectively. Sixteen shared regulators of chloroplast biogenesis were identified, 14 of which were syntenic homologs in maize and S. viridis. In sorghum (Sorghum bicolor), a third C 4 grass, we found that 82% of these trans-factors were also differentially expressed in either M or BS cells. Taken together, these data provide, to our knowledge, the first quantification of convergence in transcript abundance in the M and BS cells from independent lineages of C 4 grasses. Furthermore, the repeated recruitment of syntenic homologs from large gene families strongly implies that parallel evolution of both structural genes and trans-factors underpins the polyphyletic evolution of this highly complex trait in the monocotyledons.

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Section: Regulators Underlying Patterns Of Convergence In C 4 M and Bcontrasting

confidence: 66%

Evolutionary Convergence of Cell-Specific Gene Expression in Independent Lineages of C4 Grasses

et al. 2014

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“…These TSSs were significantly overrepresented in the W+ compared with the G+ library. Identical gTSSs were found in both green and white libraries in the case of the photosynthesis genes psbA, psaA, and psbN, which were shown to be transcribed from PEP promoters in chloroplasts (Zghidi et al, 2007;Swiatecka-Hagenbruch et al, 2007). TpsbA-80 and TpsbN-46 were additionally verified by 59-RACE (see Supplemental Data Set 3 online).…”

Section: The Primary Transcriptome Of Annotated Genesmentioning

confidence: 87%

The Primary Transcriptome of Barley Chloroplasts: Numerous Noncoding RNAs and the Dominating Role of the Plastid-Encoded RNA Polymerase

et al. 2012

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Gene expression in plastids of higher plants is dependent on two different transcription machineries, a plastid-encoded bacterial-type RNA polymerase (PEP) and a nuclear-encoded phage-type RNA polymerase (NEP), which recognize distinct types of promoters. The division of labor between PEP and NEP during plastid development and in mature chloroplasts is unclear due to a lack of comprehensive information on promoter usage. Here, we present a thorough investigation into the distribution of PEP and NEP promoters within the plastid genome of barley (Hordeum vulgare). Using a novel differential RNA sequencing approach, which discriminates between primary and processed transcripts, we obtained a genome-wide map of transcription start sites in plastids of mature first leaves. PEP-lacking plastids of the albostrians mutant allowed for the unambiguous identification of NEP promoters. We observed that the chloroplast genome contains many more promoters than genes. According to our data, most genes (including genes coding for photosynthesis proteins) have both PEP and NEP promoters. We also detected numerous transcription start sites within operons, indicating transcriptional uncoupling of genes in polycistronic gene clusters. Moreover, we mapped many transcription start sites in intergenic regions and opposite to annotated genes, demonstrating the existence of numerous noncoding RNA candidates.

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“…Thus, PsbN represents a plastid-encoded protein that shows the characteristics of an authentic PSII assembly factor. A single transcription factor, SIG3, has been shown to be primarily important for the expression of psbN (Zghidi et al, 2007). Most likely additional factors are required for fine-tuning and adjusting PsbN expression at the posttranscriptional level for the establishment of early PSII assembly in a concerted way.…”

Section: Discussion Psbn Is Present In Stroma Lamellae and Is Not A Cmentioning

confidence: 99%

PsbN Is Required for Assembly of the Photosystem II Reaction Center in Nicotiana tabacum

et al. 2014

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ORCID ID: 0000-0003-2973-9514 (J.M.)The chloroplast-encoded low molecular weight protein PsbN is annotated as a photosystem II (PSII) subunit. To elucidate the localization and function of PsbN, encoded on the opposite strand to the psbB gene cluster, we raised antibodies and inserted a resistance cassette into PsbN in both directions. Both homoplastomic tobacco (Nicotiana tabacum) mutants ΔpsbN-F and ΔpsbN-R show essentially the same PSII deficiencies. The mutants are extremely light sensitive and failed to recover from photoinhibition. Although synthesis of PSII proteins was not altered significantly, both mutants accumulated only ;25% of PSII proteins compared with the wild type. Assembly of PSII precomplexes occurred at normal rates, but heterodimeric PSII reaction centers (RCs) and higher order PSII assemblies were not formed efficiently in the mutants. The ΔpsbN-R mutant was complemented by allotopic expression of the PsbN gene fused to the sequence of a chloroplast transit peptide in the nuclear genome. PsbN represents a bitopic trans-membrane peptide localized in stroma lamellae with its highly conserved C terminus exposed to the stroma. Significant amounts of PsbN were already present in dark-grown seedling. Our data prove that PsbN is not a constituent subunit of PSII but is required for repair from photoinhibition and efficient assembly of the PSII RC.

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Nucleus-encoded plastid sigma factor SIG3 transcribes specifically the psb N gene in plastids

Cited by 79 publications

References 52 publications

Evolutionary Convergence of Cell-Specific Gene Expression in Independent Lineages of C4 Grasses

Evolutionary Convergence of Cell-Specific Gene Expression in Independent Lineages of C4 Grasses

The Primary Transcriptome of Barley Chloroplasts: Numerous Noncoding RNAs and the Dominating Role of the Plastid-Encoded RNA Polymerase

PsbN Is Required for Assembly of the Photosystem II Reaction Center in Nicotiana tabacum

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