scholarly journals Natural and laboratory mutations in kuzbanian are associated with heavy metal stress phenotypes in Drosophila melanogaster

2016 ◽  
Author(s):  
Hung Le Manh ◽  
Lain Guio ◽  
Miriam Merenciano ◽  
Quirze Rovira ◽  
Maite G. Barrón ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Drosophila Melanogaster ◽  
Target Gene ◽  
Target Genes ◽  
Heavy Metal Stress ◽  
Wild Type ◽  
Induced Mutations ◽  
Zinc Stress ◽  
High Concentrations ◽  
Transcription Factor 1

ABSTRACTOrganisms must cope with altered environmental conditions such as high concentrations of heavy metals. Stress response to heavy metals is mediated by the metal-responsive transcription factor 1 (MTF-1), which is conserved from Drosophila to humans. MTF-1 binds to metal response elements (MREs) and changes the expression of target genes. kuzbanian (kuz), a metalloendopeptidase that activates the evolutionary conserved Notch signaling pathway, has been identified as an MTF-1 target gene. We have previously identified a putatively adaptive transposable element in the Drosophila melanogaster genome, named FBti0019170, inserted in a kuz intron. In this work, we investigated whether laboratory-induced mutations in kuz are associated with zinc stress phenotypes. We found that both embryos and adult flies overexpressing kuz are more tolerant to zinc compared with wild-type flies. On the other hand, we found that the effect of FBti0019170 on zinc stress tolerance depends on developmental stage and genetic background. Moreover, in the majority of the genetic backgrounds analyzed, FBti0019170 has a deleterious effect in unpolluted environments in pre-adult stages. These results highlight the complexity of natural mutations and suggest that besides laboratory-induced mutations natural mutations need to be studied in order to accurately characterize gene function and evolution.

BCL6, p53 and Molecular Targeted Therapy in B-Cell Lymphomas.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1484-1484 ◽  
Author(s):  
Leandro C.A. Cerchietti ◽  
Jose M. Polo ◽  
Gustavo F. Da Silva ◽  
Steve M. Dowdy ◽  
Catoretti M. Giorgio ◽  
...  
Keyword(s):  
Targeted Therapy ◽  
B Cell ◽  
Target Gene ◽  
Target Genes ◽  
Wild Type ◽  
B Cell Lymphomas ◽  
Lymphoma Cells ◽  
Sequential Administration ◽  
Wild Type P53

Abstract The BCL6 transcriptional repressor is an oncogene often constitutively expressed in diffuse large B-cell lymphomas (DLBCL). The oncogenic mechanism of action of BCL6 presumably involves repression of its direct target genes. We recently developed a targeted therapy agent (called BPI - BCL6 peptide inhibitor) that specifically blocks transcriptional repression by BCL6, and which causes apoptosis in lymphoma cells in vitro and in vivo. We present here potent and stable derivatives of BPI able to specifically eradicate lymphoma cells after a single dose in vitro. Expression array studies of BCL6 target genes reactivated by BPI revealed that one such gene is the p53 tumor suppressor. p53 was also recently shown to be BCL6 target gene by Phan et. al., Nature 2004. We find that BCL6 represses p53 in DLBCL cells through recruitment of the SMRT and N-CoR corepressors, which explains how BPI, which blocks recruitment of these corepressors, reactivates p53. We next wished to determine the contribution of BCL6-mediated repression of p53 to lymphomagenesis, and how p53 modulation might affect BCL6 targeted therapy strategies for DLBCL. We found that BPI could induce p53 target gene expression in DLBCL cells with wild-type p53 and that small molecules or peptides that block p53 rescue apoptosis induced by BPI. In contrast, although BPI also induces p53 in DLCBL cells with mutant p53, there was no activation of p53 target genes and no rescue by p53 blocking molecules. However BPI causes apoptosis of DLBCL cells regardless of p53 status indicating the BCL6 mediates its oncogenic actions through both p53 dependent and independent pathways. p53 is usually wild-type in DLBCL and our analysis of >100 patients show that p53 protein is, surprisingly, still expressed in these tumors. These data suggest that p53 is not fully active in DLBCL cells, consistent with the fact that we found that BCL6 also directly represses upstream activators of p53 such as Chk1 and ATR. BCL6 blockade thus can fully restore activity of p53, both by increasing its expression levels and by enhancing its activation by upstream mediators. Accordingly, sequential administration of p53 activating molecules that enhance p53 activity, potently synergizes with BPI in killing lymphoma cells. BPI also synergizes with chemotherapy drugs that act in part through p53, such as doxorubicin. From these studies we conclude that i) BCL6 mediates lymphomagenesis by direct repression of p53 and upstream target gene pathways; ii) BCL6 positive lymphomas are dependent on BCL6 for their survival regardless of whether p53 is wild type or mutated; iii) Sequential targeting of BCL6 and p53 with BPI and a p53 activating molecule or doxorubicin is likely to be a highly effective therapeutic regimen for patients with DLBCL, especially for the majority who have wild-type p53; iv) The new BPI derivatives are sufficiently potent and stable to be tested in the clinical setting.

scholarly journals Molecular cloning of suppressor of sable, a Drosophila melanogaster transposon-mediated suppressor.

1986 ◽  
Vol 6 (5) ◽  
pp. 1520-1528 ◽  
Author(s):  
D Y Chang ◽  
B Wisely ◽  
S M Huang ◽  
R A Voelker
Keyword(s):  
Drosophila Melanogaster ◽  
Dna Sequences ◽  
Insertion Site ◽  
Hybrid Dysgenesis ◽  
P Element ◽  
Dna Transformation ◽  
Wild Type ◽  
Induced Mutations ◽  
X Ray ◽  
Element Insertion

A hybrid dysgenesis-induced allele [su(s)w20] associated with a P-element insertion was used to clone sequences from the su(s) region of Drosophila melanogaster by means of the transposon-tagging technique. Cloned sequences were used to probe restriction enzyme-digested DNAs from 22 other su(s) mutations. None of three X-ray-induced or six ethyl methanesulfonate-induced su(s) mutations possessed detectable variation. Seven spontaneous, four hybrid dysgenesis-induced, and two DNA transformation-induced mutations were associated with insertions within 2.0 kilobases (kb) of the su(s)w20 P-element insertion site. When the region of DNA that included the mutational insertions was used to probe poly(A)+ RNAs, a 5-kb message was detected in wild-type RNA that was present in greatly reduced amounts in two su(s) mutations. By using strand-specific probes, the direction of transcription of the 5-kb message was determined. The mutational insertions lie in DNA sequences near the 5' end of the 5-kb message. Three of the seven spontaneous su(s) mutations are associated with gypsy insertions, but they are not suppressible by su(Hw).

scholarly journals Analysis of the Doublesex Female Protein in Drosophila melanogaster: Role in Sexual Differentiation and Behavior and Dependence on Intersex

Genetics ◽  
1999 ◽  
Vol 152 (4) ◽  
pp. 1653-1667 ◽  
Author(s):  
Julie A Waterbury ◽  
Larry L Jackson ◽  
Paul Schedl
Keyword(s):  
Drosophila Melanogaster ◽  
Sex Determination ◽  
Target Genes ◽  
Negative Regulator ◽  
Wild Type ◽  
Binding Properties ◽  
Behavioral Abnormalities ◽  
Female Specific ◽  
And Behavior ◽  
Dna Binding Properties

Abstract doublesex (dsx) is unusual among the known sex-determination genes of Drosophila melanogaster in that functional homologs are found in distantly related species. In flies, dsx occupies a position near the bottom of the sex determination hierarchy. It is expressed in male- and female-specific forms and these proteins function as sex-specific transcription factors. In the studies reported here, we have ectopically expressed the female Dsx protein (DsxF) from a constitutive promoter and examined its regulatory activities independent of other upstream factors involved in female sex determination. We show that it functions as a positive regulator of female differentiation and a negative regulator of male differentiation. As predicted by the DNA-binding properties of the Dsx protein, DsxF and DsxM compete with each other for the regulation of target genes. In addition to directing sex-specific differentiation, DsxF plays an important role in sexual behavior. Wild-type males ectopically expressing DsxF are actively courted by other males. This acquisition of feminine sex appeal is likely due to the induction of female pheromones by DsxF. More extreme behavioral abnormalities are observed when DsxF is ectopically expressed in dsx- XY animals; these animals are not only courted by, but also copulate with, wild-type males. Finally, we provide evidence that intersex is required for the feminizing activities of DsxF and that it is not regulated by the sex-specific splicing cascade.

scholarly journals Genome-Wide Identification of Metal Tolerance Genes in Potato (Solanum Tuberosum): Response to Two Heavy Metal Stress

2021 ◽  
Author(s):  
Dandan Li ◽  
Guandi He ◽  
Weijun Tian ◽  
Yun Huang ◽  
Lulu Meng ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Solanum Tuberosum ◽  
Gene Family ◽  
Transmembrane Domain ◽  
Metal Tolerance ◽  
Cadmium Stress ◽  
Heavy Metal Stress ◽  
Metal Stress ◽  
Zinc Stress

Abstract Metal tolerance proteins play an important role in the transport and tolerance of divalent heavy metals in plant species. Potatoes are an important food crop whose yields can be deeply affected by heavy metals. However, there is a lack of information concerning the members and function of the MTP gene family in Solanum tuberosum. In this study, we identified and screened 11 MTP genes in potatoes which we named as StMTP1 to StMTP11 based on their positions on the chromosomes. Phylogenetic analysis divided these 11 MTP genes into three subfamilies; Mn-MTP, Zn-MTP and Zn/Fe-MTP. HXXXD and DXXXD conserved motifs were found on or around the transmembrane domain II and transmembrane domain V of these proteins. The highly conserved histidine and aspartic acid residues may be related to the transport of metal ions. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis showed that the expression levels of StMTP9 and StMTP10 in leaf tissues increased by around 24-fold following cadmium stress for 24 hours. We hypothesize that StMTP9 and StMTP10 respond to cadmium stress. StMTP11 showed the highest level of expression in stem tissues after 6 hours of zinc stress at more than 13 times the level of expression in controls indicating that StMTP11 is more sensitive to zinc stress. In summary, our results further the current understanding of the molecular mechanisms regulated by members of the MTP gene family in plant responses to heavy metal stress.

Genotypic and Phenotypic Characterization of the Drosophila melanogaster Olfactory Mutation Indifferent

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1577-1587
Author(s):  
Matthew Cobb
Keyword(s):  
Drosophila Melanogaster ◽  
Methyl Esters ◽  
Phenotypic Characterization ◽  
Deletion Mapping ◽  
Wild Type ◽  
Induced Mutations ◽  
Olfactory Responses ◽  
Mutant Character ◽  
Type Character ◽  
The Right

Two Drosophila melanogaster third chromosomes carrying the EMS-induced mutations IndifferentA (IndfA) and IndifferentB (IndfB), previously isolated from larvae showing an anosmia when stimulated with nonanol, were recombined with a multi-marked chromosome in order to localize the mutant character(s). Recombinant strains were tested for their larval olfactory responses and classed as either mutant or wild type; both Indf characters were found to be located on the right arm of the chromosome, between ebony and claret. Deletion mapping suggests that the Indifferent wild-type character is a haplo-insufficiency and that IndfA and IndfB are located in cytological region 96A2-7. Deficiencies and both mutant strains were tested with 14 closely related odors (alcohols, acetates, acids and methyl esters, between eight and 10 carbons long). When stimulated with methyl octanoate, IndfA and IndfB appeared recessive; noncomplementation was observed for this phenotype in IndfA/IndfB hybrids indicating that the two characters are allelic. The overall responses of IndfA, IndfB and the deficiencies indicate that Indf is involved in processing organic odors of between eight and 10 carbons in length.

scholarly journals Molecular Analysis of Diepoxybutane-Induced Mutations at the rosy Locus of Drosophila melanogaster

Genetics ◽  
1987 ◽  
Vol 115 (2) ◽  
pp. 323-331
Author(s):  
J T Reardon ◽  
C A Liljestrand-Golden ◽  
R L Dusenbery ◽  
P D Smith
Keyword(s):  
Drosophila Melanogaster ◽  
Molecular Analysis ◽  
Molecular Level ◽  
Genetic Material ◽  
Regulatory Sequences ◽  
Wild Type ◽  
Induced Mutations ◽  
Base Pairs ◽  
Restriction Patterns ◽  
Induced Mutants

ABSTRACT We have analyzed at the molecular level diepoxybutane-induced mutants determined to have lesions affecting expression of the ry locus. Of the 21 mutants analyzed here, genetic analysis suggested that five were putative deficiencies involving ry and adjacent lethal loci. However, molecular analysis confirmed that only two of these five putative deficiencies were in fact deletions detectable by the methods used in the analysis. The remaining 16 mutants were viable as homozygotes, suggesting that their lesions were confined to the ry locus. Seven of these 16 intragenic mutants were determined to be deletions of genetic material as evidenced by altered restriction patterns relative to the wild type patterns. Thus, nine of 21 (43%) diepoxybutane-induced mutants are due to deletions ranging in size from approximately 50 base pairs to more than 8 kilobase pairs. Most of the deletions (seven of nine or 78%) are intragenic and less than 250 base pairs in size; it seems that most, if not all, affect coding rather than regulatory sequences.

scholarly journals Visualizing Dynamic E2F-Mediated Repression In Vivo

2006 ◽  
Vol 26 (12) ◽  
pp. 4448-4461 ◽  
Author(s):  
Monica Agromayor ◽  
Elzbieta Wloga ◽  
Benedetta Naglieri ◽  
John Abrashkin ◽  
Kapil Verma ◽  
...  
Keyword(s):  
Target Gene ◽  
Target Genes ◽  
Suppressor Gene ◽  
Mrna Levels ◽  
Wild Type ◽  
Retinoblastoma Tumor Suppressor ◽  
Ets Family ◽  
Retinoblastoma Tumor

ABSTRACT Although many E2F target genes have been identified recently, very little is known about how any single E2F site controls the expression of an E2F target gene in vivo. To test the requirement for a single E2F site in vivo and to learn how E2F-mediated repression is regulated during development and tumorigenesis, we have constructed a novel series of wild-type and mutant Rb promoter-LacZ transgenic reporter lines that allow us to visualize the activity of a crucial E2F target in vivo, the retinoblastoma tumor suppressor gene (Rb). Two mutant Rb promoter-LacZ constructs were used to evaluate the importance of a single E2F site or a nearby activator (Sp1/Ets) site that is found mutated in low-penetrance retinoblastomas. The activity of the wild-type Rb promoter is dynamic, varying spatially and temporally within the developing nervous system. While loss of the activator site silences the Rb promoter, loss of the E2F site stimulates its activity in the neocortex, retina, and trigeminal ganglion. Surprisingly, E2F-mediated repression of Rb does not act globally or in a static manner but, instead, is a highly dynamic process in vivo. Using neocortical extracts, we detected GA-binding protein α (GABPα, an Ets family member) bound to the activator site and both E2F1 and E2F4 bound to the repressor site of the Rb promoter in vitro. Additionally, we detected binding of both E2F1 and E2F4 to the Rb promoter in vivo using chromatin immunoprecipitation analysis on embryonic day 13.5 brain. Unexpectedly, we detect no evidence for Rb promoter autoregulation in neuroendocrine tumors from Rb +/−; RbP-LacZ mice that undergo loss of heterozygosity at the Rb locus, in contrast to the situation in human retinoblastomas where high RB mRNA levels are found. In summary, this study provides the first demonstration that loss of an E2F site is critical for target gene repression in vivo and underscores the complexity of the Rb and E2F family network in vivo.

Gene transactivation without direct DNA binding defines a novel gain-of-function for PML-RARα

Blood ◽  
2008 ◽  
Vol 111 (3) ◽  
pp. 1634-1643 ◽  
Author(s):  
Sake van Wageningen ◽  
Marleen C. Breems-de Ridder ◽  
Jeannet Nigten ◽  
Gorica Nikoloski ◽  
Claudia A. J. Erpelinck-Verschueren ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Fusion Protein ◽  
Myeloid Leukemia ◽  
Target Genes ◽  
Terminal Differentiation ◽  
Wild Type ◽  
Gain Of Function ◽  
Proliferation And Differentiation ◽  
High Concentrations ◽  
Acute Myeloid

Abstract PML-RARα is the causative oncogene in 5% to 10% of the cases of acute myeloid leukemia. At physiological concentrations of retinoic acid, PML-RARα silences RARα target genes, blocking differentiation of the cells. At high concentrations of ligand, it (re)activates the transcription of target genes, forcing terminal differentiation. The study of RARα target genes that mediate this differentiation has identified several genes that are important for proliferation and differentiation control in normal and malignant hematopoietic cells. In this paper, we show that the PML-RARα fusion protein not only interferes with the transcription of regular RARα target genes. We show that the ID1 and ID2 promoters are activated by PML-RARα but, unexpectedly, not by wild-type RARα/RXR. Our data support a model in which the PML-RARα fusion protein regulates a novel class of target genes by interaction with the Sp1 and NF-Y transcription factors, without directly binding to the DNA, defining a gain-of-function for the oncoprotein.

scholarly journals The effect of elevated Zn concentrations on seed germination and young seedling growth of Ailanthus altissima (Mill.) swingle

2014 ◽  
pp. 145-157
Author(s):  
Sladjana Samuilov ◽  
Danijela Djunisijevic-Bojovic ◽  
Matilda Djukic ◽  
Jelena Rakovic
Keyword(s):  
Heavy Metals ◽  
Seed Germination ◽  
Seedling Growth ◽  
Zinc Sulfate ◽  
Heavy Metal Stress ◽  
Inhibitory Effect ◽  
Ailanthus Altissima ◽  
High Concentration ◽  
High Concentrations ◽  
Invasive Tree Species

Some heavy metals such as Zn are essential micronutrients for plants. However, in a high concentration in soils they could cause repression of growth with toxicity symptoms. It is therefore very important to investigate the species that are tolerant to high concentration of zinc which have the ability to survive on soils contaminated with heavy metals. This paper presents an investigation of the effect of elevated Zn concentrations on the germination and seedling growth of the invasive tree species Ailanthus altissima (Swingle) Mill., aimed at a better understanding of its adaptation ability to heavy metal stress and potential use in phytoremediation. Seeds of Ailanthus altissima were treated with Zn concentrations of 25, 100 and 250 ?M in form of zinc sulfate. After germination, the seedlings at the stage of first leaf development were transferred into a growing chamber in the hydroponic system where zinc sulfate was added in the concentrations of 100, 250 and 500 ?M. The results showed that Zn treatments, including the highest concentration, have caused a reduction in seed germination parameters. Considering the hypocotyl and radicle length, there was no significant statistical difference among the treatments, but further growth of young seedlings in hydroponics under high concentrations of Zn, cause an inhibition of the root system growth and repress development of assimilating organs. Seeds and seedlings of A. altissima are tolerant to elevated Zn concentrations at early stages of development. However, later on with leaves development, the inhibitory effect of the strongest concentrations is expressed.

Autonomous concentration-dependent activation and repression of Kruppel by hunchback in the Drosophila embryo

Development ◽  
1994 ◽  
Vol 120 (10) ◽  
pp. 3043-3049 ◽  
Author(s):  
C. Schulz ◽  
D. Tautz
Keyword(s):  
Target Gene ◽  
Target Genes ◽  
Early Embryo ◽  
Drosophila Embryo ◽  
Gap Gene ◽  
Low Concentrations ◽  
Localization Signal ◽  
Regulatory Effects ◽  
High Concentrations

The subdivision of the anterior-posterior axis in Drosophila is achieved by a cascade of spatially regulated transcription factors which form short-range gradients at the syncytial blastoderm stage. These factors are assumed to have concentration-dependent regulatory effects on their target genes. However, there is so far little direct in vivo evidence that a single factor can autonomously activate and repress a given target gene. We have analysed here the regulatory capabilities of the gap gene hunchback by creating an artificial gradient of hunchback in the early embryo. This was achieved by providing the maternally expressed mRNA of hunchback with the anterior localization signal of the bicoid RNA. The effects of this artificial hunchback gradient were then studied in different types of mutant background. We show that under these conditions hb is autonomously capable of activating the target gene Kruppel at low concentrations and repressing it at high concentrations. In addition, we show that the artificially created hunchback gradient can organize a large part of the segment pattern, although it is expressed at a different position and in a different shape than the wild-type gradient of hunchback.

Sign in / Sign up

Export Citation Format

Share Document