Thetef1 box, a ubiquitouscis-acting element involved in the activation of plant genes that are highly expressed in cycling cells

Regad, Farid; Hervé, Christine; Marinx, Olivier; Bergounioux, Catherine; Trémousaygue, Dominique; Lescure, Bernard

doi:10.1007/bf02191710

Cited by 35 publications

(33 citation statements)

References 48 publications

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“…When either of the two PCR fragments corresponding to the cyclin box of B-type cyclins were used as probes, mRNAs of about 2 kb long referred to as NtcycB were detected within a rather narrow window of expression coinciding with the mitotic phase. In agreement with previous studies (20), the level of the mRNA encoding the translation elongation factor (EF-1 ␣) remained relatively constant throughout the cell cycle, thus providing an internal loading control.…”

Section: Resultssupporting

confidence: 90%

Multiple A-type cyclins express sequentially during the cell cycle in Nicotiana tabacum BY2 cells

Reichheld

Chaubet

Shen

et al. 1996

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

109

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Four full-length and one partial cDNA clones encoding four different A-type cyclins were isolated from a tobacco S-phase-specific library. The corresponding mRNAs displayed sequential appearance and disappearance during the cell cycle of highly synchronized suspension-cultured tobacco cells. Sequence analysis showed that the plant A-type cyclins can be subdivided into three distinct structural groups that are likely to be represented in every plant species. Two of the isolated tobacco cyclins belonging to the same group were highly expressed throughout S and G 2 phases but showed different kinetics of induction at the G 1 ͞S transition. Another one belonging to a second group was induced at mid-S phase and expressed until mid-M phase. A similar expression pattern was previously reported for a tobacco cyclin belonging to the third group. This sequential expression of multiple A-type cyclins in one type of plant cells makes a clear distinction from the situation in animal cells in which only one A-type cyclin exists in a given species. Furthermore, the expression of the different A-type cyclin genes responded differently upon a block at mid-S phase by DNA synthesis inhibitors. These results suggest that the multiple A-type cyclins act at different steps of the plant cell cycle and, therefore, exert distinct functions. In contrast, the expression of B-type cyclins was restricted to a narrow window corresponding to the M phase.Our knowledge of the eukaryotic cell cycle has progressed considerably during the last few years, by the finding that protein kinases play a central role in the cell cycle. The activity of the protein kinases depends on the association between a cyclin-dependent serine͞threonine kinase (cdk) as the catalytic moiety and a cyclin as a regulatory subunit. The activity of the complexes is further regulated through phosphorylation͞dephosphorylation mechanisms and binding to inhibitors (1). In animal cells, distinct cdks associating sequentially with different cyclins determine the substrate specificity of the complexes and monitor the cell cycle transitions at the G 1 ͞S and G 2 ͞M major checkpoints (2, 3). These sequential associations result from stage-specific synthesis and degradation of the cyclins while the catalytic subunit is present throughout the cell cycle. The animal cyclins have been subdivided into mitotic (A-and B-type) and G 1 (C-, D-, and E-type) cyclins according to sequence homologies and expression patterns. While the G 1 cyclins are involved in progression through G 1 phase and at the G 1 ͞S transition, the mitotic A-and B-type cyclins are essential in progression through G 2 phase and at the G 2 ͞M transition. In addition, the A-type cyclin has also been shown to play essential functions in DNA replication during S phase (4-6).It has been recently shown that the basic components of the cell cycle machinery are similar in plants and animals (7). cdk-like cDNAs and genes have been isolated from several mono-and dicotyledonous plants and shown to share about 60% sequence ...

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Section: Resultssupporting

confidence: 90%

Multiple A-type cyclins express sequentially during the cell cycle in Nicotiana tabacum BY2 cells

Reichheld

Chaubet

Shen

et al. 1996

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

109

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“…For example, the polyadenylation site of the AT.I.24-9 gene and the transcription start point of the EF-I~ A1 gene are only separated by 300 bp. This small region contains cis elements involved in the regulation of EF-lcx gene expression (Curie et al 1993;Regad et al 1995).…”

Section: Discussionmentioning

confidence: 99%

“…Within the duplication a fragment of 57 bp including the TATA box and a putative cisregulatory element of EF-I~ genes, the telo box, is deleted . Conversely, the tef box, a ubiquitous element conferring overexpression of genes in dividing cells (Regad et al 1995), is still present in the duplication (Fig. 4A).…”

Section: Sequence Duplicationsmentioning

confidence: 99%

Genome DNA sequencing around the EF-1 alpha multigene locus of Arabidopsis thaliana indicates a high gene density and a shuffling of noncoding regions.

Trémousaygue¹,

Bardet²,

Dabos³

et al. 1997

Genome Res.

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in Arabidopsis thaliana, EF-lc~ proteins are encoded by a multigene family of four members. Three of them are clustered at the same locus, which was positioned 24 cM from the top of chromosome 1. A region of DNA spanning 63 kb around these locus was sequenced and analyzed. One main characteristic of the locus is the mosaic organization of both genes and intergenic regions. Fourteen genes were identified, among which only four were already described, and other unidentified are most likely present. Functionally diverse genes are found at close intervals. Exon and intron distribution is highly variable at this locus, one gene being split into at least 20 introns. Several duplications were found within the sequenced segment both in coding and noncoding regions, including two gene families. Moreover, a sequence corresponding to the S' noncoding region of the EF-IoL genes and harboring a S' intervening sequence is duplicated and found upstream of several genes, suggesting that noncoding regions can be shuffled during evolution.

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“…1B). Tobacco RNR1 genes are cell cycle-regulated and show maximum expression in S phase and a significant gene induction at the G 2 /M transition, compared with the constitutive expression of the EF1␣ gene (30). Probing with the coding region of tobacco RNR1a cDNA revealed both RNR1 mRNAs (RNR1a and RNR1b), since their coding regions share 89.2% sequence identity (31).…”

Section: Cell Cycle Expression Of the Rnr1bmentioning

confidence: 99%

S Phase and Meristem-specific Expression of the Tobacco RNR1b Gene Is Mediated by an E2F Element Located in the 5′ Leader Sequence

Chabouté

Clément

Philipps

2002

Journal of Biological Chemistry

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The RB/E2F pathway is involved in the control of the G 1 /S transition of the eukaryotic cell cycle where various S phase genes are activated by specific E2F factors. Ribonucleotide reductase (RNR) plays an essential role in the DNA synthesis pathway. Earlier studies showed that there are at least two RNR1 genes (RNR1a and RNR1b) and one RNR2 gene in tobacco. In synchronized tobacco BY2 cells, RNR1b gene expression is at its highest level in S phase. To investigate transcriptional regulation of the RNR1b gene, its promoter region was cloned and sequenced. Unlike its animal counterparts, the tobacco RNR1b promoter contains a consensus E2F-binding site. Surprisingly, this site is found in the leader sequence of the gene. We show here by gel shift analysis and antibody competition that one nuclear complex specifically binds this motif, and an E2F factor is part of this complex. Using reporter gene analysis, tobacco RNR1b promoter activity was detected during S phase in synchronized cells and in plant meristematic tissues. Mutation of the E2F element substantially reduced both activities. For the first time in plants, a single E2F motif found in the leader sequence plays an important role in the meristem and S phase-specific expression of the tobacco RNR1b gene.Progression of the cell cycle is associated with the phasespecific induction of genes whose products control the cell cycle or are involved in DNA replication (1). Transcription of several genes induced at the G 1 /S transition is mainly controlled by the E2F pathway (2). E2F complexes can act either as transcription repressors or activators depending on their target genes and the phase of the cell cycle. While transcription repression is generally achieved by binding of retinoblasma-type proteins (RB) 1 to E2F factors (3), repression of the PAI-1 gene is carried out by direct binding of E2F to its target motif (4). Transcriptional activation is triggered when the E2F factor is associated to its DP partner. E2F-binding sites (TTTC/GC/GCGC) were identified in numerous gene promoters (5). Some genes, such as cdc2 or B-Myb, appear to be strongly derepressed during the transition from G 0 to G 1 (i.e. quiescence to growth), while others, such as the p107 and DHFR genes, are up-regulated at the G 1 /S transition (6).E2F and DP factors (7-12) as well as RB proteins have been recently identified in plants (13), suggesting that the control of G 1 /S-phase-specific transcription in plants could be similar to that found in animals. Up to now, a few E2F target genes have been characterized in plants. The two E2F motifs identified in the tobacco RNR2 promoter were shown to specifically interact with a tobacco E2F factor and to mediate up-regulation of the promoter at the G 1 /S transition of the cell cycle (14). In addition, it was shown that Arabidopsis E2F1 factor binds an E2F motif in the promoter of a S-phase-regulated gene AtCDC6 (10). Alternatively, two E2F cis-elements were found in the promoter of tobacco gene encoding the proliferating cell nuclear antigen (PC...

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Thetef1 box, a ubiquitouscis-acting element involved in the activation of plant genes that are highly expressed in cycling cells

Cited by 35 publications

References 48 publications

Multiple A-type cyclins express sequentially during the cell cycle in Nicotiana tabacum BY2 cells

Multiple A-type cyclins express sequentially during the cell cycle in Nicotiana tabacum BY2 cells

Genome DNA sequencing around the EF-1 alpha multigene locus of Arabidopsis thaliana indicates a high gene density and a shuffling of noncoding regions.

S Phase and Meristem-specific Expression of the Tobacco RNR1b Gene Is Mediated by an E2F Element Located in the 5′ Leader Sequence

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