Synthesis of Escherichia coli carbomoylphosphate synthetase initiates at a UUG codon

The ribosome binding region of the messenger RNA for the Esherichia coli car A gene contains two adjacent putative translational start codons, UUG and AUU, both of them unusual. By Edman degradation and mass spectrometry of purified car A protein, we show that only UUG is used in vivo. Translation initiation at UUG in car A appears about half as efficient as at AUG in lacZ. Copyright © 1985, Wiley Blackwell. All rights reservedSCOPUS: ar.jinfo:eu-repo/semantics/publishe

On the role of the Shine-Dalgarno sequence in determining the efficiency of translation initiation at a weak start codon in the car operon of Escherichia coli K12

Translation of the carA gene is efficiently initiated at the intrinsically weak UUG codon. A single nucleotide substitution changing the Shine-Dalgarno box of carA (GGAGG) into the sequence TGAGG reduces translation of carA sevenfold. This result supports the view that extensive complementarity between the Shine-Dalgarno sequence and 16 S RNA contributes significantly to the efficiency of translation when the latter starts at a weak initiation triplet. © 1988.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Proteomic studies of a sugar-beet plant resistant to rhizomania

Immuno-Maldi (2001-2004) : aspects fondamentaux et appliqués du développement de biosenseurs (protein arrays, tissue arrays

Expression of the Beet necrotic yellow vein virus p25 protein induces hormonal changes and a root branching phenotype in Arabidopsis thaliana

International audienceThe RNA-3-encoded p25 protein was previously characterized as one of the major symptom determinants of the Beet necrotic yellow vein virus. Previous analyses reported the influence of the p25 protein in root proliferation phenotype observed in rhizomania disease on infected sugar beets (Beta vulgaris). A transgenic approach was developed, in which the p25 protein was constitutively expressed in Arabidopsis thaliana Columbia (Col-0) ecotype in order to provide new clues as to how the p25 protein might promote alone disease development and symptom expression. Transgenic plants were characterized by Southern blot and independent lines carrying single and multiple copies of the transgene were selected. Mapping of the T-DNA insertion was performed on the monocopy homozygote lines. P25 protein was localized both in the nucleus and in the cytoplasm of epidermal and root cells of transgenic plants. Although A. thaliana was not described as a susceptible host for BNYVV infection, abnormal root branching was observed on p25 protein-expressing A. thaliana plants. Moreover, these transgenic plants were more susceptible than wild-type plants to auxin analog treatment (2,4-D) but more resistant to methyl jasmonate (MeJA), abscisic acid (ABA) and to lesser extend to salicylic acid (SA). Hormonal content assays measuring plant levels of auxin (IAA), jasmonate (JA) and ethylene precursor (ACC) revealed major hormonal changes. Global transcript profiling analyses on roots displayed differential gene expressions that could corroborate root branching phenotype and stress signaling modifications

A high efficiency technique for the generation of transgenic sugar beets from stomatal guard cells

An optimized protocol has been developed for the efficient and rapid genetic modification of sugar beet (Beta vulgaris L.). A polyethylene glycol-mediated DNA transformation technique could be applied to protoplast populations enriched specifically for a single totipotent cell type derived from stomatal guard cells, to achieve high transformation frequencies. Bialaphos resistance, conferred by the pat gene, produced a highly efficient selection system. The majority of plants were obtained within 8 to 9 weeks and were appropriate for plant breeding purposes. All were resistant to glufosinate-ammonium-based herbicides. Detailed genomic characterization has verified transgene integration, and progeny analysis showed Mendelian inheritance

The Role of a Pseudo-Response Regulator Gene in Life Cycle Adaptation and Domestication of Beet

Highlights: Map-based cloning of B in beet led to isolation of the PRR gene BvBTC1 BvBTC1 controls life cycle through differential regulation of the BvFT1/BvFT2 module BvBTC1 mediates floral transition in response to both long days and vernalization Beet domestication involved selection of a rare Bvbtc1 allele conferring bienniality Summary: Life cycle adaptation to latitudinal and seasonal variation in photoperiod and temperature is a major determinant of evolutionary success in flowering plants. Whereas the life cycle of the dicotyledonous model species Arabidopsis thaliana is controlled by two epistatic genes, FLOWERING LOCUS C and FRIGIDA [1,2,3], three unrelated loci (VERNALIZATION 1–3) determine the spring and winter habits of monocotyledonous plants such as temperate cereals [4,5,6]. In the core eudicot species Beta vulgaris, whose lineage diverged from that leading to Arabidopsis shortly after the monocot-dicot split 140 million years ago [7,8], the bolting locus B [9] is a master switch distinguishing annuals from biennials. Here, we isolated B and show that the pseudo-response regulator gene BOLTING TIME CONTROL 1 (BvBTC1), through regulation of the FLOWERING LOCUS T genes [10], is absolutely necessary for flowering and mediates the response to both long days and vernalization. Our results suggest that domestication of beets involved the selection of a rare partial loss-of-function BvBTC1 allele that imparts reduced sensitivity to photoperiod that is restored by vernalization, thus conferring bienniality, and illustrate how evolutionary plasticity at a key regulatory point can enable new life cycle strategies.Peer reviewe