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Manuel Duval

Bio: Manuel Duval is an academic researcher from Pfizer. The author has contributed to research in topics: Biotinylation & Biotin. The author has an hindex of 12, co-authored 31 publications receiving 1233 citations. Previous affiliations of Manuel Duval include Centre national de la recherche scientifique & University of New Haven.

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Journal ArticleDOI
TL;DR: It is highlighted that germination vigor depends on multiple biochemical and molecular variables and their characterization is expected to deliver new markers of seed quality that can be used in breeding programs and/or in biotechnological approaches to improve crop yields.
Abstract: Germination vigor is driven by the ability of the plant embryo, embedded within the seed, to resume its metabolic activity in a coordinated and sequential manner. Studies using “-omics” approaches support the finding that a main contributor of seed germination success is the quality of the messenger RNAs stored during embryo maturation on the mother plant. In addition, proteostasis and DNA integrity play a major role in the germination phenotype. Because of its pivotal role in cell metabolism and its close relationships with hormone signaling pathways regulating seed germination, the sulfur amino acid metabolism pathway represents a key biochemical determinant of the commitment of the seed to initiate its development toward germination. This review highlights that germination vigor depends on multiple biochemical and molecular variables. Their characterization is expected to deliver new markers of seed quality that can be used in breeding programs and/or in biotechnological approaches to improve crop yields.

787 citations

Journal ArticleDOI
TL;DR: In vivo assays in yeast demonstrate that AtNAM encodes a transcription factor and that the NAC domain includes a specific DNA binding domain (DBD), which potentially folds into a helix-turn-helix motif that specifically binds to the CaMV 35S promoter.
Abstract: The petunia NAM and Arabidopsis ATAF1 and CUC2 genes define the conserved NAC domain. In petunia, loss-of-function nam mutants result in embryos that fail to elaborate shoot apical meristems (SAM), and nam seedlings do not develop shoots and leaves. We have isolated a NAC domain gene, AtNAM, from an Arabidopsis developing seed cDNA library. Expression of AtNAM mRNA is restricted primarily to the region of the embryo including the SAM. The AtNAM gene contains three exons and is located on Chromosome 1. In vivo assays in yeast demonstrate that AtNAM encodes a transcription factor and that the NAC domain includes a specific DNA binding domain (DBD). The AtNAM DBD is contained within a 60 amino acid region which potentially folds into a helix-turn-helix motif that specifically binds to the CaMV 35S promoter. The putative transcriptional activation domain is located in the C-terminal region of the protein, a highly divergent region among NAC domain-containing genes. The Arabidopsis genome contains 90 predicted NAC domain genes; we refer to these collectively as the AtNAC superfamily. The first two exons of all members of this superfamily encode the NAC domain. Most AtNAC genes contain three exons with the last exon encoding an activation domain. A subfamily of AtNAC genes contains additional terminal exons coding for protein domains whose functions are unknown.

312 citations

Journal ArticleDOI
TL;DR: The results of CNBr cleavage experiments suggest that biotin is covalently bound to the protein, and the temporal and spatial pattern of expression of SBP65 is described, with regard to the possibility that in plants, as in mammals, biotin plays a specialized role in cell growth and differentiation.
Abstract: Mature dry pea seeds contain three major biotinylated proteins. Two of these of subunit molecular mass about 75 kDa and 200 kDa are associated with 3-methylcrotonyl-CoA carboxylase (EC 6.4.1.4) and acetyl-CoA carboxylase activities (EC 6.4.1.2) respectively. The third does not exhibit any of the biotin-dependent carboxylase activities found in higher organisms and represents the major part of the total protein-bound biotin in the seeds. This novel protein has been purified from a whole pea seed extract. Because in SDS/polyacrylamide gels the protein migrates with an apparent molecular mass of about 65 kDa, it is referred to as SBP65, for 65 kDa seed biotinylated protein. The molecular mass of native SBP65 is greater than 400 kDa, suggesting that the native protein assumes a polymeric structure, resulting from the association of six to eight identical subunits. The results of CNBr cleavage experiments suggest that biotin is covalently bound to the protein. The stoichiometry is 1 mol of biotin per 1 mol of 65 kDa polypeptide. The temporal and spatial pattern of expression of SBP65 is described. SBP65 is specifically expressed in the seeds, being absent from leaf, root, stem, pod and flower tissues of pea plants. The level of SBP65 increases dramatically during seed development. The protein is not detectable in very young seeds. Its accumulation pattern parallels that for storage proteins, being maximally expressed in the mature dry seeds. SBP65 disappears at a very high rate during seed germination. The level of free biotin has also been evaluated for various organs of pea plants. In all proliferating tissues examined (young developing seeds, leaf, root, stem, pod and flower tissues), free biotin is in excess of protein-bound biotin. Only in the mature dry seeds is protein-bound biotin (i.e. that bound to SBP65) in excess of free biotin. These temporal expression patterns, and the strict organ specificity for expression of SBP65, are discussed with regard to the possibility that in plants, as in mammals, biotin plays a specialized role in cell growth and differentiation.

54 citations

Journal ArticleDOI
TL;DR: Molecular analysis of the protein sequence reveals an extremely hydrophilic protein containing several repeated motifs that suggest that SBP65 belongs to the LEA (late embryogenesis-abundant) group of proteins.
Abstract: Seeds of Pisum sativum contain a biotinyl polypeptide called SBP65 that behaves as a putative sink for the free vitamin, representing more than 90% of the total protein-bound biotin in mature seeds. A cDNA encoding SBP65 was cloned and sequenced. The deduced primary structure of the protein was confirmed by protein sequencing. Peptide sequencing also indicated binding of the biotin to lysine 103. The biotinylation domain of SBP65 differs markedly from that of presently known biotin enzymes. Molecular analysis of the protein sequence reveals an extremely hydrophilic protein containing several repeated motifs. These properties, as well as the temporal and spatial patterns of expression of this protein, suggest that SBP65 belongs to the LEA (late embryogenesis-abundant) group of proteins.

48 citations

Journal ArticleDOI
TL;DR: A survey reveals that the way in which genetic sequences are claimed in granted patents are heterogeneous and imprecise, which may lead to questions regarding their validity.
Abstract: A survey reveals that the way in which genetic sequences are claimed in granted patents are heterogeneous and imprecise, which may lead to questions regarding their validity.

41 citations


Cited by
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01 Dec 1941-Nature
TL;DR: The Pharmacological Basis of Therapeutics, by Prof. Louis Goodman and Prof. Alfred Gilman, New York: The Macmillan Company, 1941, p.
Abstract: The Pharmacological Basis of Therapeutics A Textbook of Pharmacology, Toxicology and Therapeutics for Physicians and Medical Students. By Prof. Louis Goodman and Prof. Alfred Gilman. Pp. xiii + 1383. (New York: The Macmillan Company, 1941.) 50s. net.

2,686 citations

Journal ArticleDOI
TL;DR: The complete NAC recognition sequence, containing CATGT and harboring CACG as the core DNA binding site is determined, which indicates that other interacting factors may be necessary for the induction of erd1 in Arabidopsis under stress conditions.
Abstract: The MYC-like sequence CATGTG plays an important role in the dehydration-inducible expression of the Arabidopsis thaliana EARLY RESPONSIVE TO DEHYDRATION STRESS 1 (ERD1) gene, which encodes a ClpA (ATP binding subunit of the caseinolytic ATP-dependent protease) homologous protein. Using the yeast one-hybrid system, we isolated three cDNA clones encoding proteins that bind to the 63-bp promoter region of erd1, which contains the CATGTG motif. These three cDNA clones encode proteins named ANAC019, ANAC055, and ANAC072, which belong to the NAC transcription factor family. The NAC proteins bound specifically to the CATGTG motif both in vitro and in vivo and activated the transcription of a beta-glucuronidase (GUS) reporter gene driven by the 63-bp region containing the CATGTG motif in Arabidopsis T87 protoplasts. The expression of ANAC019, ANAC055, and ANAC072 was induced by drought, high salinity, and abscisic acid. A histochemical assay using P(NAC)-GUS fusion constructs showed that expression of the GUS reporter gene was localized mainly to the leaves of transgenic Arabidopsis plants. Using the yeast one-hybrid system, we determined the complete NAC recognition sequence, containing CATGT and harboring CACG as the core DNA binding site. Microarray analysis of transgenic plants overexpressing either ANAC019, ANAC055, or ANAC072 revealed that several stress-inducible genes were upregulated in the transgenic plants, and the plants showed significantly increased drought tolerance. However, erd1 was not upregulated in the transgenic plants. Other interacting factors may be necessary for the induction of erd1 in Arabidopsis under stress conditions.

1,286 citations

Journal ArticleDOI
TL;DR: The biological and molecular functions of the NAC family are summarized, paying particular attention to the intricate regulation of NAC protein level and localization, and to the first indications of Nac participation in transcription factor networks.

1,195 citations

Journal ArticleDOI
TL;DR: Findings suggest that VND6 and VND7 genes are transcription switches for plant metaxylem and protoxylem vessel formation.
Abstract: Land plants evolved xylem vessels to conduct water and nutrients, and to support the plant. Microarray analysis with a newly established Arabidopsis in vitro xylem vessel element formation system and promoter analysis revealed the possible involvement of some plant-specific NAC-domain transcription factors in xylem formation. VASCULAR-RELATED NAC-DOMAIN6 (VND6) and VND7 can induce transdifferentiation of various cells into metaxylem- and protoxylem-like vessel elements, respectively, in Arabidopsis and poplar. A dominant repression of VND6 and VND7 specifically inhibits metaxylem and protoxylem vessel formation in roots, respectively. These findings suggest that these genes are transcription switches for plant metaxylem and protoxylem vessel formation.

1,016 citations

Journal ArticleDOI
TL;DR: A comprehensive analysis of NAC family genes in Oryza sativa and Arabidopsis thaliana found 13 common sequence motifs from transcriptional activation regions in the C-terminal regions of predicted NAC proteins that probably diverged having correlations with NAC domain structures.
Abstract: The NAC domain was originally characterized from consensus sequences from petunia NAM and from Arabidopsis ATAF1, ATAF2, and CUC2. Genes containing the NAC domain (NAC family genes) are plant-specific transcriptional regulators and are expressed in various developmental stages and tissues. We performed a comprehensive analysis of NAC family genes in Oryza sativa (a monocot) and Arabidopsis thaliana (a dicot). We found 75 predicted NAC proteins in full-length cDNA data sets of O. sativa (28,469 clones) and 105 in putative genes (28,581 sequences) from the A. thaliana genome. NAC domains from both predicted and known NAC family proteins were classified into two groups and 18 subgroups by sequence similarity. There were a few differences in amino acid sequences in the NAC domains between O. sativa and A. thaliana. In addition, we found 13 common sequence motifs from transcriptional activation regions in the C-terminal regions of predicted NAC proteins. These motifs probably diverged having correlations with NAC domain structures. We discuss the relationship between the structure and function of the NAC family proteins in light of our results and the published data. Our results will aid further functional analysis of NAC family genes.

908 citations