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Chabouté, Marie‐Edith; Combettes, Bruno; Clément, Bernadette; Gigot, Claude; Philipps, Gabriel

doi:10.1023/a:1006083318906

Cited by 31 publications

(8 citation statements)

References 39 publications

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“…The elevated level of folates in these tissues might reflect a high demand for one-carbon units for the nucleotide synthesis during the S-phase, as the genome is doubled. In agreement with this, the expression of ribonucleotide reductase, the enzyme involved in nucleotide synthesis, is also found to be induced at the G1/S transition (Chabouté et al, 1998). Thus, it is very likely that genes of the folate biosynthesis pathway are also regulated in a cell-cycle dependent manner.…”

Section: Distribution Of Folatesmentioning

confidence: 58%

Folates in Plants: Research Advances and Progress in Crop Biofortification

et al. 2017

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Folates, also known as B9 vitamins, serve as donors and acceptors in one-carbon (C1) transfer reactions. The latter are involved in synthesis of many important biomolecules, such as amino acids, nucleic acids and vitamin B5. Folates also play a central role in the methyl cycle that provides one-carbon groups for methylation reactions. The important functions fulfilled by folates make them essential in all living organisms. Plants, being able to synthesize folates de novo, serve as an excellent dietary source of folates for animals that lack the respective biosynthetic pathway. Unfortunately, the most important staple crops such as rice, potato and maize are rather poor sources of folates. Insufficient folate consumption is known to cause severe developmental disorders in humans. Two approaches are employed to fight folate deficiency: pharmacological supplementation in the form of folate pills and biofortification of staple crops. As the former approach is considered rather costly for the major part of the world population, biofortification of staple crops is viewed as a decent alternative in the struggle against folate deficiency. Therefore, strategies, challenges and recent progress of folate enhancement in plants will be addressed in this review. Apart from the ever-growing need for the enhancement of nutritional quality of crops, the world population faces climate change catastrophes or environmental stresses, such as elevated temperatures, drought, salinity that severely affect growth and productivity of crops. Due to immense diversity of their biochemical functions, folates take part in virtually every aspect of plant physiology. Any disturbance to the plant folate metabolism leads to severe growth inhibition and, as a consequence, to a lower productivity. Whereas today's knowledge of folate biochemistry can be considered very profound, evidence on the physiological roles of folates in plants only starts to emerge. In the current review we will discuss the implication of folates in various aspects of plant physiology and development.

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Section: Distribution Of Folatesmentioning

confidence: 58%

Folates in Plants: Research Advances and Progress in Crop Biofortification

et al. 2017

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“…One gene is already expressed at high levels at the beginning of the time course and its expression is restricted to S phase, as described (31). In contrast, another gene is highly expressed in S phase and reappears at lower levels during M phase, whereas a third is M phase-specific.…”

Section: Identification and Characterization Of Cell Cycle-modulated mentioning

confidence: 83%

Transcriptome analysis during cell division in plants

Breyne

Dreesen

Vandepoele

et al. 2002

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

138

142

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Using synchronized tobacco Bright Yellow-2 cells and cDNAamplified fragment length polymorphism-based genomewide expression analysis, we built a comprehensive collection of plant cell cycle-modulated genes. Approximately 1,340 periodically expressed genes were identified, including known cell cycle control genes as well as numerous unique candidate regulatory genes. A number of plant-specific genes were found to be cell cycle modulated. Other transcript tags were derived from unknown plant genes showing homology to cell cycle-regulatory genes of other organisms. Many of the genes encode novel or uncharacterized proteins, indicating that several processes underlying cell division are still largely unknown.

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“…In a previous report, we identified two RNR1 cDNAs and one RNR2 cDNA (31). Since the coding regions of both RNR1 cDNAs are closely related, 3Ј-specific probes were necessary to distinguish the expression pattern of each cDNA.…”

Section: Discussionmentioning

confidence: 99%

“…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). However, using a 3Ј-specific probe, we show that the RNR1b gene is strongly expressed in S phase and very weakly at the G 2 /M transition.…”

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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Untitled

Cited by 31 publications

References 39 publications

Folates in Plants: Research Advances and Progress in Crop Biofortification

Folates in Plants: Research Advances and Progress in Crop Biofortification

Transcriptome analysis during cell division in plants

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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