scholarly journals STY1 and STY2 promote the formation of apical tissues during Arabidopsis gynoecium development

Development ◽  
2002 ◽  
Vol 129 (20) ◽  
pp. 4707-4717 ◽  
Author(s):  
Sandra Kuusk ◽  
Joel J. Sohlberg ◽  
Jeff A. Long ◽  
Ingela Fridborg ◽  
Eva Sundberg
Keyword(s):  
Double Mutant ◽  
Ectopic Expression ◽  
Ring Finger ◽  
Regional Differentiation ◽  
35S Promoter ◽  
Insertion Mutation ◽  
Wild Type ◽  
Transposon Insertion ◽  
Visible Effect ◽  
Gynoecium Development

Gynoecium ontogenesis in Arabidopsis is accomplished by the co-ordinated activity of genes that control patterning and the regional differentiation of tissues, and ultimately results in the formation of a basal ovary, a short style and an apical stigma. A transposon insertion in the STYLISH1 (STY1) gene results in gynoecia with aberrant style morphology, while an insertion mutation in the closely related STYLISH2 (STY2) gene has no visible effect on gynoecium development. However, sty1-1 sty2-1 double mutant plants exhibit an enhanced sty1-1 mutant phenotype and are characterized by a further reduction in the amount of stylar and stigmatic tissues and decreased proliferation of stylar xylem. These data imply that STY1 and STY2 are partially redundant and that both genes promote style and stigma formation and influence vascular development during Arabidopsis gynoecium development. Consistently, STY1 and STY2 are expressed in the apical parts of the developing gynoecium and ectopic expression of either STY1 or STY2 driven by the CaMV 35S promoter is sufficient to transform valve cells into style cells. STY1::GUS and STY2::GUS activity is detected in many other organs as well as the gynoecium, suggesting that STY1 and STY2 may have additional functions. This is supported by the sty1-1 sty2-1 double mutants producing rosette and cauline leaves with a higher degree of serration than wild-type leaves. STY1 and STY2 are members of a small gene family, and encode proteins with a RING finger-like motif. Double mutant analyses indicate that STY1 genetically interacts with SPATULA and possibly also with CRABS CLAW.

scholarly journals ExsY and CotY Are Required for the Correct Assembly of the Exosporium and Spore Coat of Bacillus cereus

2006 ◽  
Vol 188 (22) ◽  
pp. 7905-7913 ◽  
Author(s):  
Matt J. Johnson ◽  
Sarah J. Todd ◽  
David A. Ball ◽  
Andrew M. Shepherd ◽  
Patricia Sylvestre ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Double Mutant ◽  
Insertion Mutant ◽  
Spore Coat ◽  
Coat Proteins ◽  
Wild Type ◽  
Western Blots ◽  
Transposon Insertion ◽  
Spore Coat Proteins ◽  
Late Stages

ABSTRACT The exosporium-defective phenotype of a transposon insertion mutant of Bacillus cereus implicated ExsY, a homologue of B. subtilis cysteine-rich spore coat proteins CotY and CotZ, in assembly of an intact exosporium. Single and double mutants of B. cereus lacking ExsY and its paralogue, CotY, were constructed. The exsY mutant spores are not surrounded by an intact exosporium, though they often carry attached exosporium fragments. In contrast, the cotY mutant spores have an intact exosporium, although its overall shape is altered. The single mutants show altered, but different, spore coat properties. The exsY mutant spore coat is permeable to lysozyme, whereas the cotY mutant spores are less resistant to several organic solvents than is the case for the wild type. The exsY cotY double-mutant spores lack exosporium and have very thin coats that are permeable to lysozyme and are sensitive to chloroform, toluene, and phenol. These spore coat as well as exosporium defects suggest that ExsY and CotY are important to correct formation of both the exosporium and the spore coat in B. cereus. Both ExsY and CotY proteins were detected in Western blots of purified wild-type exosporium, in complexes of high molecular weight, and as monomers. Both exsY and cotY genes are expressed at late stages of sporulation.

scholarly journals Neither the Bvg− Phase nor thevrg6 Locus of Bordetella pertussis Is Required for Respiratory Infection in Mice

1998 ◽  
Vol 66 (6) ◽  
pp. 2762-2768 ◽  
Author(s):  
Guillermo Martinez de Tejada ◽  
Peggy A. Cotter ◽  
Ulrich Heininger ◽  
Andrew Camilli ◽  
Brian J. Akerley ◽  
...  
Keyword(s):  
Respiratory Infection ◽  
Bordetella Pertussis ◽  
Whooping Cough ◽  
Ectopic Expression ◽  
Sensory Transduction ◽  
Insertion Mutation ◽  
Wild Type ◽  
Animal Reservoir ◽  
Phenotypic Alteration

ABSTRACT In Bordetella species, the BvgAS sensory transduction system mediates an alteration between the Bvg+ phase, characterized by expression of adhesins and toxins, and the Bvg− phase, characterized by the expression of motility and coregulated phenotypes in Bordetella bronchiseptica and by the expression of vrg loci in Bordetella pertussis. Since there is no known environmental or animal reservoir for B. pertussis, the causative agent of whooping cough, it has been assumed that this phenotypic alteration must occur within the human host during infection. Consistent with this hypothesis was the observation that a B. pertussis mutant, SK6, containing a TnphoA insertion mutation in a Bvg-repressed gene (vrg6) was defective for tracheal and lung colonization in a mouse model of respiratory infection (D. T. Beattie, R. Shahin, and J. Mekalanos, Infect. Immun. 60:571–577, 1992). This result was inconsistent, however, with the observation that a Bvg+ phase-locked B. bronchiseptica mutant was indistinguishable from the wild type in its ability to establish a persistent respiratory infection in rabbits and rats (P. A. Cotter and J. F. Miller, Infect. Immun. 62:3381–3390, 1994; B. J. Akerley, P. A. Cotter, and J. F. Miller, Cell 80:611–620, 1995). To directly address the role of Bvg-mediated signal transduction in B. pertussis pathogenesis, we constructed Bvg+ and Bvg− phase-locked mutants and compared them with the wild type for their ability to colonize the respiratory tracts of mice. Our results show that the Bvg+phase of B. pertussis is necessary and sufficient for respiratory infection. By constructing a strain with a deletion in thebvgR regulatory locus, we also show that ectopic expression of Bvg− phase phenotypes decreases the efficiency of colonization, underscoring the importance of Bvg-mediated repression of gene expression in vivo. Finally, we show that the virulence defect present in strain SK6 cannot be attributed to the vrg6mutation. These data contradict an in vivo role for the Bvg− phase of B. pertussis.

scholarly journals The RNA-dependent DNA methylation pathway is required to restrict SPOROCYTELESS/NOZZLE expression to specify a single female germ cell precursor in Arabidopsis

Development ◽  
2020 ◽  
Vol 147 (23) ◽  
pp. dev194274
Author(s):  
Marta A. Mendes ◽  
Rosanna Petrella ◽  
Mara Cucinotta ◽  
Edoardo Vignati ◽  
Stefano Gatti ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Double Mutant ◽  
Higher Plants ◽  
Ectopic Expression ◽  
Wild Type ◽  
Cell Precursor ◽  
Single Female ◽  
Methylation Pathway ◽  
Female Germ Cell ◽  
Female Germline

ABSTRACTIn higher plants, the female germline is formed from the megaspore mother cell (MMC), a single cell in the premeiotic ovule. Previously, it was reported that mutants in the RNA-dependent DNA methylation (RdDM) pathway might be involved in restricting the female germline to a single nucellus cell. We show that the DRM methyltransferase double mutant drm1drm2 also presents ectopic enlarged cells, consistent with supernumerary MMC-like cells. In wild-type ovules, MMC differentiation requires SPOROCYTELESS/NOZZLE (SPL/NZZ), as demonstrated by the spl/nzz mutant failing to develop an MMC. We address the poorly understood upstream regulation of SPL/NZZ in ovules, showing that the RdDM pathway is important to restrict SPL/NZZ expression. In ago9, rdr6 and drm1drm2 mutants, SPL/NZZ is expressed ectopically, suggesting that the multiple MMC-like cells observed might be attributable to the ectopic expression of SPL/NZZ. We show that the ovule identity gene, SEEDSTICK, directly regulates AGO9 and RDR6 expression in the ovule and therefore indirectly regulates SPL/NZZ expression. A model is presented describing the network required to restrict SPL/NZZ expression to specify a single MMC.

scholarly journals Mutations Decreasing Intrinsic β-Lactam Resistance Are Linked to Cell Division in the Nosocomial Pathogen Acinetobacter baumannii

2016 ◽  
Vol 60 (6) ◽  
pp. 3751-3758 ◽  
Author(s):  
Daniel Knight ◽  
Daniela D. Dimitrova ◽  
Susan D. Rudin ◽  
Robert A. Bonomo ◽  
Philip N. Rather
Keyword(s):  
Cell Division ◽  
Acinetobacter Baumannii ◽  
Double Mutant ◽  
Mrna Levels ◽  
Wild Type ◽  
Nosocomial Pathogen ◽  
Content Type ◽  
Tn5 Transposon ◽  
Transposon Insertion ◽  
Similar Phenotype

Transposon mutagenesis was used to identify novel determinants of intrinsic β-lactam resistance inAcinetobacter baumannii. An EZ-Tn5 transposon insertion in a gene corresponding to the A1S_0225 sequence resulted in a 4-fold decrease in resistance to ampicillin, cefotaxime, imipenem, and ceftriaxone but did not alter resistance to other classes of antibiotics. Based on this phenotype, the gene was designatedblhA(β-lactamhypersusceptibility). TheblhA::EZ-Tn5 mutation conferred a similar phenotype inA. baumanniistrain ATCC 17978. The wild-typeblhAgene complemented theblhA::EZTn5 insertion and restored β-lactam resistance levels back to wild-type levels. TheblhAmutation also increased β-lactam susceptibility in anadeB adeJdouble mutant, indicating that theblhAmutation acted independently of these efflux systems to mediate susceptibility. In addition, mRNA levels for theblaOXAandblaADCβ-lactamase genes were not altered by theblhAmutation. TheblhAmutation resulted in a prominent cell division and morphological defect, with cells exhibiting a highly elongated phenotype, combined with large bulges in some cells. TheblhAgene is unique toAcinetobacterand likely represents a novel gene involved in cell division. Three additional mutations, inzipA,zapA, andftsK, each of which encode predicted cell division proteins, also conferred increased β-lactam susceptibility, indicating a common link between cell division and intrinsic β-lactam resistance inA. baumannii.

scholarly journals Over-expression of the Hybrid Aspen Homeobox PttKN1 Gene in Red Leaf Beet Induced Altered Coloration of Leaves

2015 ◽  
Vol 43 (1) ◽  
pp. 35-40
Author(s):  
Quanle XU ◽  
Mei-yu RUAN ◽  
Ying-jie TAO ◽  
Xin HU
Keyword(s):  
Transgenic Plants ◽  
Ectopic Expression ◽  
Kanamycin Resistance ◽  
Pcr Analysis ◽  
35S Promoter ◽  
Wild Type ◽  
Morphological Alterations ◽  
Pttkn1 Gene ◽  
Transgenic Lines ◽  
Morphological Modification

PttKN1 (Populus tremula × tremuloides KNOTTED1) gene belongs to the KNOXI gene family. It plays an important role in plant development, typically in meristem initiation, maintenance and organogenesis, and potentially in plant coloration. To investigate the gene functions further, it was introduced into red leaf beet by the floral dip method mediated via Agrobacterium tumefaciens. The transformants demonstrated typical phenotypes as with other PttKN1 transformants. These alterations were very different from the morphology of the wild type. Among them, morphological modification of changed color throughout the entire plant from claret of wild type to yellowish green was the highlight in those transgenic PttKN1-beet plants. The result of spraying selection showed that the PttKN1-beet plants had kanamycin resistance. PCR assay of the 35S-Promoter, NPTII and PttKN1 gene, PCR-Southern analysis of the NPTII and PttKN1 gene showed that the foreign PttKN1 gene had successfully integrated into the genome of beet plant. Furthermore, the results of RT-PCR analysis showed that the gene was ectopic expressed in transgenic plants. These data suggested that there is a correlation between the ectopic expression of PttKN1 gene and morphological alterations of beet plants. Pigment content assay showed that betaxanthins concentrations shared little difference between wild type and transgenic lines, while betacyanins content in transgenic plants was sharply decreased, indicating that the altered plant coloration of the transgenic beet plants may be caused by the changed betacyanins content. The tyrosinase study suggested that the sharply decreased of betacyanins content in transgenic plants was caused via the decreased tyrosinase level. Therefore, the reason for the altered plant coloration may be due to partial inhibition of betacyanin biosynthesis that was induced via the pleiotropic roles of PttKN1 gene.

scholarly journals Ectopic Expression of Jatropha curcas TREHALOSE-6-PHOSPHATE PHOSPHATASE J Causes Late-Flowering and Heterostylous Phenotypes in Arabidopsis but not in Jatropha

2019 ◽  
Vol 20 (9) ◽  
pp. 2165 ◽  
Author(s):  
Mei-Li Zhao ◽  
Jun Ni ◽  
Mao-Sheng Chen ◽  
Zeng-Fu Xu
Keyword(s):  
Flower Development ◽  
Developmental Process ◽  
Transgenic Arabidopsis ◽  
Ectopic Expression ◽  
Cauliflower Mosaic Virus ◽  
35S Promoter ◽  
Wild Type ◽  
Late Flowering ◽  
Male Flowers ◽  
Sucrose Level

Trehalose-6-phosphate (T6P) phosphatase (TPP), a dephosphorylating enzyme, catalyzes the dephosphorylation of T6P, generating trehalose. In Jatropha, we found six members of the TPP family. Five of them JcTPPA, JcTPPC, JcTPPD, JcTPPG, and JcTPPJ are highly expressed in female flowers or male flowers, or both, suggesting that members of the JcTPP family may participate in flower development in Jatropha. The wide expression of JcTPPJ gene in various organs implied its versatile roles and thus was chosen for unraveling its biological functions during developmental process. We constructed an overexpression vector of JcTPPJ cDNA driven by the cauliflower mosaic virus (CaMV) 35S promoter for genetic transformation. Compared with control Arabidopsis plants, 35S:JcTPPJ transgenic Arabidopsis plants presented greater sucrose contents in their inflorescences and displayed late-flowering and heterostylous phenotypes. Exogenous application of sucrose to the inflorescence buds of wild-type Arabidopsis repressed the development of the perianth and filaments, with a phenocopy of the 35S:JcTPPJ transgenic Arabidopsis. These results suggested that the significantly increased sucrose level in the inflorescence caused (or induced) by JcTTPJ overexpression, was responsible for the formation of heterostylous flower phenotype. However, 35S:JcTPPJ transgenic Jatropha displayed no obvious phenotypic changes, implying that JcTPPJ alone may not be sufficient for regulating flower development in Jatropha. Our results are helpful for understanding the function of TPPs, which may regulate flower organ development by manipulating the sucrose status in plants.

scholarly journals Identification of genes involved in the differentiation of R7y and R7p photoreceptor cells in Drosophila

2019 ◽  
Author(s):  
James B Earl ◽  
Lauren A Vanderlinden ◽  
Laura M Saba ◽  
Steven G Britt
Keyword(s):  
Cell Fate ◽  
Compound Eye ◽  
Ectopic Expression ◽  
Photoreceptor Cells ◽  
Biological Processes ◽  
Cell Fate Specification ◽  
Wild Type ◽  
Transposon Insertion ◽  
Yellow Type ◽  
Driver Line

AbstractThe R7 and R8 photoreceptor cells of the Drosophila compound eye mediate color vision. Throughout the majority of the eye, these cells occur in two principal types of ommatidia. Approximately 35% of ommatidia are of the pale type and express Rh3 in R7 cells and Rh5 in R8 cells. The remaining 65% are of the yellow type and express Rh4 in R7 cells and Rh6 in R8 cells. The specification of an R8 cell in a pale or yellow ommatidium depends on the fate of the adjacent R7 cell. However, pale and yellow R7 cells are specified by a stochastic process that requires the genes spineless, tango and klumpfuss. To identify additional genes involved in this process we performed a genetic screen using a collection of 480 P{EP} transposon insertion strains. We identified genes that when inactivated and/or ectopically expressed in R7 cells resulted in a significantly altered percentage of Rh3 expressing R7 cells (Rh3%) from wild-type. 53 strains resulted in altered Rh3% in the heterozygous inactivation arm of the screen. 36 strains resulted in altered Rh3% in the ectopic expression arm of the screen, where the P{EP} insertion strains were crossed to a sevEP-GAL4 driver line. 4 strains showed differential effects between the two screens. Analyses of these results suggest that R7 cell fate specification is sensitive to perturbations in transcription, growth inhibition, glycoprotein ligand binding, WNT signaling, ubiquitin protease activity and Ser/Thr kinase activity, among other diverse signaling and cell biological processes.

scholarly journals Mutations in the gerP Locus ofBacillus subtilis and Bacillus cereus Affect Access of Germinants to Their Targets in Spores

2000 ◽  
Vol 182 (7) ◽  
pp. 1987-1994 ◽  
Author(s):  
Javad Behravan ◽  
Haridasan Chirakkal ◽  
Anne Masson ◽  
Anne Moir
Keyword(s):  
Heat Resistance ◽  
Bacillus Cereus ◽  
Organic Molecules ◽  
Early Stage ◽  
Insertion Mutation ◽  
Structural Components ◽  
Wild Type ◽  
Transposon Insertion ◽  
Small Proteins ◽  
Gain Access

ABSTRACT The gerP1 transposon insertion mutation ofBacillus cereus is responsible for a defect in the germination response of spores to both l-alanine and inosine. The mutant is blocked at an early stage, before loss of heat resistance or release of dipicolinate, and the efficiency of colony formation on nutrient agar from spores is reduced fivefold. The protein profiles of alkaline-extracted spore coats and the spore cortex composition are unchanged in the mutant. Permeabilization ofgerP mutant spores by coat extraction procedures removes the block in early stages of germination, although a consequence of the permeabilization procedure in both wild type and mutant is that late germination events are not complete. The complete hexacistronic operon that includes the site of insertion has been cloned and sequenced. Four small proteins encoded by the operon (GerPA, GerPD, GerPB, and GerPF) are related in sequence. A homologous operon (yisH-yisC) can be found in the Bacillus subtilis genome sequence; null mutations in yisD and yisF, constructed by integrational inactivation, result in a mutant phenotype similar to that seen in B. cereus, though somewhat less extreme and equally repairable by spore permeabilization. Normal rates of germination, as estimated by loss of heat resistance, are also restored to a gerP mutant by the introduction of a cotEmutation, which renders the spore coats permeable to lysozyme. TheB. subtilis operon is expressed solely during sporulation, and is sigma K-inducible. We hypothesize that the GerP proteins are important as morphogenetic or structural components of theBacillus spore, with a role in the establishment of normal spore coat structure and/or permeability, and that failure to synthesize these proteins during spore formation limits the opportunity for small hydrophilic organic molecules, like alanine or inosine, to gain access to their normal target, the germination receptor, in the spore.

scholarly journals Analysis of maxillopedia Expression Pattern and Larval Cuticular Phenotype in Wild-Type and Mutant Tribolium

Genetics ◽  
2000 ◽  
Vol 155 (2) ◽  
pp. 721-731 ◽  
Author(s):  
Teresa D Shippy ◽  
Jianhua Guo ◽  
Susan J Brown ◽  
Richard W Beeman ◽  
Robin E Denell
Keyword(s):  
Rna Interference ◽  
Expression Pattern ◽  
Tribolium Castaneum ◽  
Expression Patterns ◽  
Ectopic Expression ◽  
Homeotic Gene ◽  
Wild Type ◽  
Double Stranded Rna ◽  
Similar Expression ◽  
Mutant Phenotypes

Abstract The Tribolium castaneum homeotic gene maxillopedia (mxp) is the ortholog of Drosophila proboscipedia (pb). Here we describe and classify available mxp alleles. Larvae lacking all mxp function die soon after hatching, exhibiting strong transformations of maxillary and labial palps to legs. Hypomorphic mxp alleles produce less severe transformations to leg. RNA interference with maxillopedia double-stranded RNA results in phenocopies of mxp mutant phenotypes ranging from partial to complete transformations. A number of gain-of-function (GOF) mxp alleles have been isolated based on transformations of adult antennae and/or legs toward palps. Finally, we have characterized the mxp expression pattern in wild-type and mutant embryos. In normal embryos, mxp is expressed in the maxillary and labial segments, whereas ectopic expression is observed in some GOF variants. Although mxp and Pb display very similar expression patterns, pb null embryos develop normally. The mxp mutant larval phenotype in Tribolium is consistent with the hypothesis that an ancestral pb-like gene had an embryonic function that was lost in the lineage leading to Drosophila.

scholarly journals OmpR and LeuO Positively Regulate the Salmonella enterica Serovar Typhi ompS2 Porin Gene

2004 ◽  
Vol 186 (10) ◽  
pp. 2909-2920 ◽  
Author(s):  
Marcos Fernández-Mora ◽  
José Luis Puente ◽  
Edmundo Calva
Keyword(s):  
Salmonella Enterica ◽  
Type Strain ◽  
Wild Type Strain ◽  
Phosphorylation Site ◽  
Regulatory Region ◽  
Random Mutagenesis ◽  
Fold Increase ◽  
Upstream Regulatory Region ◽  
Wild Type ◽  
Transposon Insertion

ABSTRACT The Salmonella enterica serovar Typhi ompS2 gene codes for a 362-amino-acid outer membrane protein that contains motifs common to the porin superfamily. It is expressed at very low levels compared to the major OmpC and OmpF porins, as observed for S. enterica serovar Typhi OmpS1, Escherichia coli OmpN, and Klebsiella pneumoniae OmpK37 quiescent porins. A region of 316 bp, between nucleotides −413 and −97 upstream of the transcriptional start point, is involved in negative regulation, as its removal resulted in a 10-fold increase in ompS2 expression in an S. enterica serovar Typhi wild-type strain. This enhancement in expression was not observed in isogenic mutant strains, which had specific deletions of the regulatory ompB (ompR envZ) operon. Furthermore, ompS2 expression was substantially reduced in the presence of the OmpR D55A mutant, altered in the major phosphorylation site. Upon random mutagenesis, a mutant where the transposon had inserted into the upstream regulatory region of the gene coding for the LeuO regulator, showed an increased level of ompS2 expression. Augmented expression of ompS2 was also obtained upon addition of cloned leuO to the wild-type strain, but not in an ompR isogenic derivative, consistent with the notion that the transposon insertion had increased the cellular levels of LeuO and with the observed dependence on OmpR. Moreover, LeuO and OmpR bound in close proximity, but independently, to the 5′ upstream regulatory region. Thus, the OmpR and LeuO regulators positively regulate ompS2.

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