A promoter identified in the 3? end of the Ac transposon can be activated by cis-acting elements in transgenic Arabidopsis lines

Cocherel, Sylvie; Peréz, Pascual; Degroote, Fabienne; Genestier, Simonne; Picard, Georges

doi:10.1007/bf00049330

Cited by 14 publications

(8 citation statements)

References 58 publications

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“…One likely explanation is that both the T-DNA and the Ds element harbor some promoter-like activity that enables transcription of CCDA. The Ds element is known to carry a promoter-like sequence at its 3Ј-end that can be activated upon integration (51). Indeed, we could detect a hybrid RNA in the ccda-2 line using a Ds element-specific primer and a CCDAspecific primer (Fig.…”

Section: Discussionmentioning

confidence: 98%

A Homolog of Prokaryotic Thiol Disulfide Transporter CcdA Is Required for the Assembly of the Cytochrome bf Complex in Arabidopsis Chloroplasts

Page¹,

Hamel²,

Gabilly³

et al. 2004

Journal of Biological Chemistry

101

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The c-type cytochromes are defined by the occurrence of heme covalently linked to the polypeptide via thioether bonds between heme and the cysteine sulfhydryls in the CXXCH motif of apocytochrome. Maintenance of apocytochrome sulfhydryls in a reduced state is a prerequisite for covalent ligation of heme to the CXXCH motif. In bacteria, a thiol disulfide transporter and a thioredoxin are two components in a thio-reduction pathway involved in c-type cytochrome assembly. We have identified in photosynthetic eukaryotes nucleus-encoded homologs of a prokaryotic thiol disulfide transporter, CcdA, which all display an N-terminal extension with respect to their bacterial counterparts. The extension of Arabidopsis CCDA functions as a targeting sequence, suggesting a plastid site of action for CCDA in eukaryotes. Using PhoA and LacZ as topological reporters, we established that Arabidopsis CCDA is a polytopic protein with within-membrane strictly conserved cysteine residues. Insertional mutants in the Arabidopsis CCDA gene were identified, and loss-of-function alleles were shown to impair photosynthesis because of a defect in cytochrome b 6 f accumulation, which we attribute to a block in the maturation of holocytochrome f, whose heme binding domain resides in the thylakoid lumen. We postulate that plastid cytochrome c maturation requires CCDA, thioredoxin HCF164, and other molecules in a membrane-associated trans-thylakoid thiol-reducing pathway.The c-type cytochromes are a virtually ubiquitous yet rather structurally diverse group of hemoproteins that reside on the so-called p-side 1 of the energy-transducing membrane systems where they function typically as electron carriers (1, 2). The c-type cytochromes are defined by the occurrence of heme covalently attached to the polypeptide via two thioether linkages between the vinyl groups of heme and the cysteine sulfhydryls in the apocytochrome (1, 3). A CXXCH 2 sequence in the apocytochrome provides the thiols for formation of the thioether bonds, and the imidazole of the histidine residue serves as one of the axial ligands of the heme. Remarkably, three distinct assembly pathways, referred to as systems I, II, and III, have emerged through genetic analysis of c-type cytochrome maturation in bacteria, chloroplasts, and mitochondria (for review, see Refs. 1 and 4 -7), an unexpected finding for what appears on the surface to be a rather simple chemical reaction (i.e. the addition of apocytochrome cysteine thiols to the vinyls of heme). Each system can be distinguished on the basis of a sequence relationship of specific assembly factors. Yet, there is an underlying assumption that the three systems are united by common biochemical requirements for holocytochrome c biogenesis (for review, see Refs. 2, 4, and 8). For instance, the need for reducing conditions appears to be inherent to the chemistry of thioether bond formation (4). Both substrates, apocytochrome c sulfhydryls and heme, need to be maintained reduced prior to the ligation of heme as indicated from in vitro and in o...

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Section: Discussionmentioning

confidence: 98%

A Homolog of Prokaryotic Thiol Disulfide Transporter CcdA Is Required for the Assembly of the Cytochrome bf Complex in Arabidopsis Chloroplasts

Page¹,

Hamel²,

Gabilly³

et al. 2004

Journal of Biological Chemistry

101

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“…Although the gene trap system was designed to recover insertions within transcription units, in some lines insertions were found outside of transcribed regions (;50% of lines reported here) or within a transcribed region of an annotated gene but in the wrong orientation (;25% of lines reported here). Theoretically, no GUS staining should be observed in such a scenario; however, it has been postulated that the GUS gene in the Trapper gene trap lines may contain a minimal promoter and can also act as an enhancer trap (Cocherel et al, 1996). Gene trap insertions within transcribed regions of annotated genes yet in the opposite direction may be tagging the antisense transcripts, since many Arabidopsis genes are also transcribed in the reverse direction (Yamada et al, 2003;Jen et al, 2005).…”

Section: Gene Trap Screeningmentioning

confidence: 99%

Gene Trap Lines Define Domains of Gene Regulation inArabidopsisPetals and Stamens

et al. 2005

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To identify genes involved in Arabidopsis thaliana petal and stamen organogenesis, we used a gene trap approach to examine the patterns of reporter expression at each stage of flower development of 1765 gene trap lines. In 80 lines, the reporter gene showed petal-and/or stamen-specific expression or lack of expression, or expression in distinct patterns within the petals and/or the stamens, including distinct suborgan domains of expression, such as tissue-specific lines marking epidermis and vasculature, as well as lines demarcating the proximodistal or abaxial/adaxial axes of the organs. Interestingly, reporter gene expression was typically restricted along the proximodistal axis of petals and stamens, indicating the importance of this developmental axis in patterning of gene expression domains in these organs. We identified novel domains of gene expression along the axis marking the midregion of the petals and apical and basal parts of the anthers. Most of the genes tagged in these 80 lines were identified, and their possible functions in petal and/or stamen differentiation are discussed. We also scored the floral phenotypes of the 1765 gene trap lines and recovered two mutants affecting previously uncharacterized genes. In addition to revealing common domains of gene expression, the gene trap lines reported here provide both useful markers and valuable starting points for reverse genetic analyses of the differentiation pathways in petal and stamen development.

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“…Two of our Arabidopsis secretion trap lines have a single insertion outside annotated genes (GT5211 and GT6249). We considered the possibility that transcription could initiate within the gene trap element (Cocherel et al, 1996) and come under the control of a tunicamycininduced enhancer, but tests indicated that these insertions are not transcriptionally induced by tunicamycin (Table III). Furthermore, GUS expression patterns were specific to individual cell types, suggesting that they do not reflect rogue transcription.…”

Section: Insertions Outside Annotated Genesmentioning

confidence: 99%

Secretion Trap Tagging of Secreted and Membrane-Spanning Proteins Using Arabidopsis Gene Traps

et al. 2003

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Secreted and membrane-spanning proteins play fundamental roles in plant development but pose challenges for genetic identification and characterization. We describe a “secretion trap” screen for gene trap insertions in genes encoding proteins routed through the secretory pathway. The gene trap transposon encodes a β-glucuronidase reporter enzyme that is inhibited by N-linked glycosylation specific to the secretory pathway. Treatment of seedlings with tunicamycin inhibits glycosylation, resulting in increased activity of secreted β-glucuronidase fusions that result from gene trap integration downstream of exons encoding signal peptides. In the 2,059 gene trap lines that we screened, 32 secretion trap expression patterns were identified in a wide variety of tissues including embryos, meristems, and the developing vasculature. Genes disrupted by the secretion traps encode putative extracellular signaling proteins, membrane transport proteins, and novel secreted proteins of unknown function missed by conventional mutagenesis and gene prediction. Secretion traps provide a unique reagent for gene expression studies and can guide the genetic combination of loss of function alleles in related genes.

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A promoter identified in the 3? end of the Ac transposon can be activated by cis-acting elements in transgenic Arabidopsis lines

Cited by 14 publications

References 58 publications

A Homolog of Prokaryotic Thiol Disulfide Transporter CcdA Is Required for the Assembly of the Cytochrome bf Complex in Arabidopsis Chloroplasts

A Homolog of Prokaryotic Thiol Disulfide Transporter CcdA Is Required for the Assembly of the Cytochrome bf Complex in Arabidopsis Chloroplasts

Gene Trap Lines Define Domains of Gene Regulation inArabidopsisPetals and Stamens

Secretion Trap Tagging of Secreted and Membrane-Spanning Proteins Using Arabidopsis Gene Traps

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