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At least 19 recordsLinked to original sources
PubMed2025

The MIR169:NF-YA module enhances biomass and yield via ARGOS in Arabidopsis and tomato.

Molecular links between miRNA: target modules regulating downstream genes for crop maturation/yield are poorly understood. Here, we report that elevated miR169d expression and concomitant reduced NF-YA2 (Nuclear Factor-Y subunit-A) target levels positively regulate vegetative growth and yield in Arabidopsis along with a shorter life cycle. In agreement, increased NF-YA2 levels in (1) NF-YA2-OE (overexpression) lines, (2) miR169d-target-mimicry lines (in which miR169d is chelated), and (3) miR169d-non-cleavable NF-YA2 resistant target lines show the opposite phenotype. Further, we find increased auxin levels in MIR169d-OE and nf-ya2 mutant lines, supporting the enrichment of 'auxin terms' in MIR169-OE transcriptome data. We show that ARGOS (auxin-regulated gene involved in organ size) is upregulated in MIR169d-OE due to reduced NF-YA2 repressor levels and that NF-YA2 directly binds the ARGOS promoter. Genetic screens of this module show that neither overexpressing miR169d in an argos mutant background nor the nf-ya2:argos double mutants rescue the argos mutant phenotype, suggesting a parallel pathway of ARGOS regulation via the MIR169:NF-YA2 node, independent of auxin. To assess the translational potential of this module in a crop, we show that Sly-MIR169-OE lines in tomato, having reduced target Sly-NF-YA10 levels, also regulate Sly-ARGOS resulting in early flowering, larger sized fruits, more fruit fresh weight, higher fruit set, early fruiting, and better shelf life than wild-type plants. In contrast, Sly-STTM169 plants inhibited for Sly-miR169 action and having increased levels of Sly-NF-YA10 have a longer life cycle with reduced biomass, decreased fruit set, and an overall reduction in yield. Thus, our findings show a conserved MIR169:NF-YA:ARGOS module which can be applied to crops for addressing future food demands.

MicroRNAs↗
PubMed1992

The argos gene encodes a diffusible factor that regulates cell fate decisions in the Drosophila eye.

The argos gene encodes a protein that is required for viability and that regulates the determination of cells in the Drosophila eye. A developmental analysis of argos mutant eyes indicates that the mystery cells, which are usually nonneuronal, are transformed into extra photoreceptors, and that supernumerary cone cells and pigment cells are also recruited. Clonal analysis indicates that argos acts nonautonomously and can diffuse over the range of several cell diameters. Conceptual translation of the argos gene suggests that it encodes a secreted protein.

Amino Acid Sequence↗
PubMed1977

Evaluation of secondary structure predictions in proteins.

Data of 33 proteins are used to compare four methods which predict secondary structure from the amino acid sequence. The prediction of alpha-helices according to the histogram method of Argos et al. (Argos, P., Schwarz, J. and Schwarz, J. (1976) Biochim. Biophys. Acta 439, 261-273) is on the average as reliable as the statistical method of Nagano (Nagano, K. (1973) J. Mol. Biol. 75, 401-420). Both methods predict helices more accurately than the stereo-chemical method of Lim (Lim, V.I. (1974) J. Mol. Biol. 88, 873-894). The method of Nagano yields the best prediction of beta-structure, while the beta-structure predictions of Lim and Argos et al. are not significantly different. The results of the alpha-helix and beta-structure predictions according to the statistical mechanical method of Tanaka and Scheraga (Tanaka, S. and Scheraga, H.A. (1976) Macromolecules 9, 168-182) are inferior to those obtained by the other three methods. For the prediction of turns, no significant difference between the methods of Nagano (Nagano, K. (1974) J. Mol. Biol. 84, 337-372) and Argos et al. was found.

Amino Acid Sequence↗
PubMed1988

The tachykinin NH2-senktide, a selective neurokinin B receptor agonist, is a very potent inhibitor of salt appetite in the rat.

The tachykinin peptide [Asp5.6, MePhe8]substance P(5-11) (NH2-senktide), a senktide analogue lacking the N-terminal succinyl group, is a selective and metabolically stable NK-3 receptor agonist. In the present study it potently inhibited salt appetite induced by sodium depletion in rats. Argo-neurokinin B, too, inhibited salt appetite, but was less potent than NH2-senktide. Neither peptide inhibited drinking behaviour induced by subcutaneous hypertonic NaCl. NH2-senktide slightly inhibited angiotensin-induced drinking, while Argo-neurokinin B was ineffective. On the other hand, eledoisin was a potent inhibitor in the 3 behavioural tests. Present results indicate that activation of NK-3 receptors is involved in the antinatriorexic action of tachykinins, and that different receptor subtypes might be involved in the different effects of tachykinins on the rat ingestive behaviour.

Animals↗
PubMed1990

Mutagenic, electrochemical, and crystallographic investigation of the cytochrome b5 oxidation-reduction equilibrium: involvement of asparagine-57, serine-64, and heme propionate-7.

A gene coding for lipase-solubilized bovine liver microsomal cytochrome b5 has been synthesized, expressed in Escherichia coli, and mutated at functionally critical residues. Characterization of the recombinant protein revealed that it has a reduction potential that is approximately 17 mV lower than that of authentic wild-type protein at pH 7 (25 degrees C). Structural studies determined that the recombinant protein differed in sequence from authentic wild-type cytochrome b5 owing to three errors in amidation status in the published sequence for the protein on which the gene synthesis was based. The structural origin of the lower reduction potential exhibited by the triple mutant has been investigated through X-ray crystallographic determination of the three-dimensional structure of this protein and is attributed to the presence of Asp-57 within 3.3 A of heme vinyl-4 in the mutant. In addition, the model developed by Argos and Mathews [Argos, P., & Mathews, F.S. (1975) J. Biol. Chem. 250, 747] for the change in cytochrome b5 oxidation state has been studied through mutation of Ser-64 to Ala. In this model, Ser-64 is postulated to stabilize the oxidized protein through H-bonding interactions with heme propionate-7 that orients this propionate group 6.2 A from the heme iron. Spectroelectrochemical studies of a mutant in which Ser-64 has been changed to an alanyl residue demonstrate that this protein has a reduction potential that is 7 mV lower than that of the wild-type protein; moreover, conversion of the heme propionate groups to the corresponding methyl esters increases the potential by 67 mV.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

Thalassemic red cells determined by different technology of blood cell analysers.

Blood samples from 12 normal cases and 30 thalassemic patients were analyzed by four blood cell analysers (the H*1, Baker 9,000RX, Coulter JT, and Argos). These four machines had different technology: light scattering using laser beam (H*1) and electronic aperture impedance (Baker 9,000RX, Coulter JT, and Argos). Analysis of normal blood samples showed comparable red cell parameters between these four machines except the value of RDW. When the thalassemic blood samples were determined using these four types of blood cell counters, many red cell parameters showed significant difference. This indicates that thalassemic red cells which are known as the abnormal cells in terms of their volume, shape, intracellular hemoglobin content, and osmotic fragility, responded differently to the reagents and technology of blood cell analysis. Calibration of the instrument using qualitatively abnormal blood sample, is recommended.

Blood Cell Count↗
PubMed1989

Identification of four conserved motifs among the RNA-dependent polymerase encoding elements.

Four consensus sequences are conserved with the same linear arrangement in RNA-dependent DNA polymerases encoded by retroid elements and in RNA-dependent RNA polymerases encoded by plus-, minus- and double-strand RNA viruses. One of these motifs corresponds to the YGDD span previously described by Kamer and Argos (1984). These consensus sequences altogether lead to 4 strictly and 18 conservatively maintained amino acids embedded in a large domain of 120 to 210 amino acids. As judged from secondary structure predictions, each of the 4 motifs, which may cooperate to form a well-ordered domain, places one invariant amino acid in or proximal to turn structures that may be crucial for their correct positioning in a catalytic process. We suggest that this domain may constitute a prerequisite 'polymerase module' implicated in template seating and polymerase activity. At the evolutionary level, the sequence similarities, gap distribution and distances between each motif strongly suggest that the ancestral polymerase module was encoded by an individual genetic element which was most closely related to the plus-strand RNA viruses and the non-viral retroposons. This polymerase module gene may have subsequently propagated in the viral kingdom by distinct gene set recombination events leading to the wide viral variety observed today.

Amino Acid Sequence↗
PubMed1992

A functional protein hybrid between the glucose transporter and the N-acetylglucosamine transporter of Escherichia coli.

The glucose and N-acetylglucosamine-specific transporters (IIGlc/IIIGlc and IIGlcNAc) of the bacterial phosphotransferase system mediate carbohydrate uptake across the cytoplasmic membrane concomitant with substrate phosphorylation. The two transporters have 40% amino acid sequence identity. Eight chimeric proteins between the two transporters were made by gene reconstruction. All hybrid proteins could be expressed, some inhibited cell growth, and one was active. The active hybrid transporter consists of the transmembrane domain (residues 1-386) of the IIGlc subunit and the two hydrophilic domains (residues 370-648) of IIGlcNAc. The N-terminal hydrophilic domain of IIGlcNAc contains the transiently phosphorylated cysteine-412. The hybrid protein is specific for glucose, which indicates that the sugar specificity determinant is in the transmembrane domain and that the cysteine from which the phosphoryl group is transferred to the substrate is not part of the binding site. The protein sequence (LKTPGRED) at which the successful fusion occurred has the characteristic properties of an interdomain oligopeptide linker (Argos, P., 1990, J. Mol. Biol. 211, 943-958).

Acetylglucosamine↗
PubMed1992

A redefinition of the Asp-Asp domain of reverse transcriptases.

The rules defining the Asp-Asp domain of RNA-dependent polymerases deduced by Argos (1988) were tested in a set of 53 putative reverse transcriptases (RTs) sequences. Since it was found that some of these rules are not followed by RTs coded by bacteria, group II introns, and non-LTR retrotransposons, we present here a more strict definition of the Asp-Asp domain.

Amino Acid Sequence↗
PubMed1984

Transcription analysis of a Bacillus subtilis arg gene following cloning in Escherichia coli in an initially unstable hybrid plasmid.

Following shotgun cloning of EcoRI fragments of Bacillus subtilis DNA in pBR322, a hybrid plasmid pUL710 was isolated which complements argC but no other auxotrophs of E. coli K12. Restriction mapping, Southern blotting and other evidence suggest that pUL710 carries an insert of 1.6 kbp, and derives, by deletion of both vector and insert sequences, from a larger but unstable initial hybrid which carried a 12 kbp EcoRI fragment from the B. subtilis chromosome. RecE-dependent integration of pUL710 into the B. subtilis chromosome demonstrated homology between the insert DNA and the argO locus of B. subtilis. pUL710 was found to confer appreciable tetracycline resistance even though the deletion presumed to stabilise the hybrid had inactivated the tet promoter. The results of analysis by Tn5 mutagenesis, transcriptional fusions and run-off in vitro transcription suggest that both the cloned argC gene and the tetracycline gene in pUL710 are expressed from a B. subtilis promoter located very close to the EcoRI cloning site.

Aldehyde Oxidoreductases↗
PubMed1992

Method for calculating 3-D coordinates from molecular stereograms.

The three-dimensional coordinates for the alpha-carbon atoms of crambin and basic pancreatic trypsin inhibitor (BPTI) were determined from the respective alpha-carbon trace stereograms using an improved Simplex algorithm. This algorithm was used in a two-step process to estimate the z-coordinate values. In one approach, an average interatomic distance value, an approximate viewing angle, and a table of digitized values for xleft, yleft and xright, yright are provided in the first step. In the second step, the z-coordinate values are derived by varying z to minimize the bond distance error (Rossmann and Argos, 1980). In another approach, only a reference bond distance table is provided along with the table of xleft, yleft and xright, yright digitized values. In the first step, the viewing angle (phi), a combined scale and viewing distance parameter (q), a rotational angular distortion from digitizing and/or photocopying (z), and translational distortion factors (xerr and yerr) are calculated. In the second step, the z-coordinate values are varied to minimize the bond distance error. RMS difference values of less than 1.5 A were obtained for both crambin and BPTI alpha-carbon atoms.

Algorithms↗
PubMed1988

The use of folding patterns in the search of protein structural similarities; a three-dimensional model of phosphoribosyl transferases.

A new way to predict the topologies of proteins of unknown three-dimensional structure is derived from the comparison of the distribution of the strongest predicted secondary structures with equivalent distributions recorded for proteins of known X-ray structures. As an illustration the tentative three-dimensional model of phosphoribosyl transferases which was proposed by Argos et al. is rediscussed.

Amino Acid Sequence↗
PubMed1991

Solution conformation of a peptide fragment representing a proposed RNA-binding site of a viral coat protein studied by two-dimensional NMR.

The first 25 amino acids of the coat protein of cowpea chlorotic mottle virus are essential for binding the encapsidated RNA. Although an alpha-helical conformation has been predicted for this highly positively charged N-terminal region [Argos, P. (1981) Virology 110, 55-62; Vriend, G., Verduin, B. J. M., & Hemminga, M. A. (1986) J. Mol. Biol. 191, 453-460], no experimental evidence for this conformation has been presented so far. In this study, two-dimensional proton NMR experiments were performed on a chemically synthesized pentacosapeptide containing the first 25 amino acids of this coat protein [Ten Kortenaar, P. B. W., Krüse, J., Hemminga, M. A., & Tesser, G. I. (1986) Int. J. Pept. Protein Res. 27, 401-413]. All resonances could be assigned by a combined use of two-dimensional correlated spectroscopy and nuclear Overhauser enhancement spectroscopy carried out at four different temperatures. Various NMR parameters indicate the presence of a conformational ensemble consisting of helical structures rapidly converting into more extended states. Differences in chemical shifts and nuclear Overhauser effects indicate that lowering the temperature induces a shift of the dynamic equilibrium toward more helical structures. At 10 degrees C, a perceptible fraction of the conformational ensemble consists of structures with an alpha-helical conformation between residues 9 and 17, likely starting with a turnlike structure around Thr9 and Arg10. Both the conformation and the position of this helical region agree well with the secondary structure predictions mentioned above.

Amino Acid Sequence↗
PubMed1978

A general method to assess similarity of protein structures, with applications to T4 bacteriophage lysozyme.

A method is proposed that permits the structural similarity between any pair of proteins to be analyzed in a completely general manner. In the proposed procedure, all possible structural segments of a given length from one protein are compared with all possible segments from the other protein. This set of comparisons reveals any structural similarities between the two proteins being compared, and also provides a basis for estimating the probability that a particular degree of structural homology could have occurred by chance. Application of the method to the comparison of T4 bacteriophage lysozyme and carp calcium-binding protein suggests that the previously reported structural similarity between parts of these two proteins [Tufty, R. M.& Kretsinger, R. H. (1975) Science 187, 167-169] is no better than would be expected by chance. On the other hand, the structural correspondence between phage lysozyme and hen egg-white lysozyme [Rossman, M.G. & Argos, P. (1976) J. Mol. Biol. 105, 75-96] does appear to be significant.

Animals↗
PubMed1990

Spectroscopic studies of wild-type and mutant "zinc finger" peptides: determinants of domain folding and structure.

The "zinc finger" model [Miller, J., McLachlan, A. D. & Klug, A. (1985) EMBO J. 4, 1609-1614; Brown, R. S., Sander, C. & Argos, P. (1985) FEBS Lett. 186, 271-274] makes both specific structural and specific functional predictions about zinc finger consensus sequences that can be tested with a combination of genetic, molecular biological, and biophysical techniques. The yeast transcription factor ADR1 contains two adjacent zinc finger domains; genetic and deletion analyses showed that amino acid substitutions and deletions in the zinc finger domains resulted in the loss of protein activity. To test the structural and folding predictions of the zinc finger model, peptides encompassing each of the ADR1 fingers were synthesized (ADR1a and ADR1b) as well as a mutant finger peptide (del138) deleted for a single amino acid residue. The folding and metal-binding characteristics of these were assessed by 1H nuclear magnetic resonance (NMR) and visible spectroscopy. While a single unique conformational species was detected for the two wild-type peptides upon tetrahedral binding of zinc, the deletion peptide did not bind zinc with tetrahedral geometry, nor did it fold into a zinc finger domain. The metal-binding and folding results found with the mutant peptide were similar to those obtained when thiol alkylation or imidazole protonation of the wild-type peptides was performed. These data indicate that ligand spacing and both thiol and imidazole participation in zinc binding are specific and necessary requirements for zinc finger folding, which provides direct support for the initial predictions of the model.

Alkylation↗