scholarly journals Analysis of the Mechanism by Which Glucose Inhibits Maltose Induction of MAL Gene Expression in Saccharomyces

Genetics ◽  
2000 ◽  
Vol 154 (1) ◽  
pp. 121-132
Author(s):  
Zhen Hu ◽  
Yingzi Yue ◽  
Hua Jiang ◽  
Bin Zhang ◽  
Peter W Sherwood ◽  
...  
Keyword(s):  
Gene Expression ◽  
Glucose Repression ◽  
Protein A ◽  
The Other ◽  
Maltose Permease ◽  
Inducer Exclusion ◽  
Glucose Inhibition ◽  
Independent Mechanism ◽  
Mal Genes

Abstract Expression of the MAL genes required for maltose fermentation in Saccharomyces cerevisiae is induced by maltose and repressed by glucose. Maltose-inducible regulation requires maltose permease and the MAL-activator protein, a DNA-binding transcription factor encoded by MAL63 and its homologues at the other MAL loci. Previously, we showed that the Mig1 repressor mediates glucose repression of MAL gene expression. Glucose also blocks MAL-activator-mediated maltose induction through a Mig1p-independent mechanism that we refer to as glucose inhibition. Here we report the characterization of this process. Our results indicate that glucose inhibition is also Mig2p independent. Moreover, we show that neither overexpression of the MAL-activator nor elimination of inducer exclusion is sufficient to relieve glucose inhibition, suggesting that glucose acts to inhibit induction by affecting maltose sensing and/or signaling. The glucose inhibition pathway requires HXK2, REG1, and GSF1 and appears to overlap upstream with the glucose repression pathway. The likely target of glucose inhibition is Snf1 protein kinase. Evidence is presented indicating that, in addition to its role in the inactivation of Mig1p, Snf1p is required post-transcriptionally for the synthesis of maltose permease whose function is essential for maltose induction.

scholarly journals Characterization of NorR Protein, a Multifunctional Regulator of norA Expression in Staphylococcus aureus

2003 ◽  
Vol 185 (10) ◽  
pp. 3127-3138 ◽  
Author(s):  
Que Chi Truong-Bolduc ◽  
Xiamei Zhang ◽  
David C. Hooper
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Efflux Pump ◽  
Protein A ◽  
Protein Overexpression ◽  
Wild Type ◽  
Liquid Media ◽  
Cell Surface Properties ◽  
Regulatory Systems

ABSTRACT We characterized a Staphylococcus aureus norA gene expression regulator, NorR, initially identified from its binding to the norA promoter. The norR gene was 444 bp in length, located ∼7 kb upstream from the norA gene, and encoded a predicted 17.6-kDa protein. Overexpression of norR in wild-type S. aureus strain ISP794 led to a fourfold decrease in sensitivity to quinolones and ethidium bromide and an increase in the level of norA transcripts, suggesting that NorR acts as a positive regulator of norA expression. Overexpression of norR in sarA and agr mutants did not alter quinolone sensitivity or levels of norA transcription, indicating that the presence of these two global regulatory systems is necessary for NorR to affect the expression of norA. Insertion and disruption of norR in ISP794 increased resistance to quinolones by 4- to 16-fold but had no effect on norA transcription, suggesting that NorR acts as a repressor for another unidentified efflux pump or pumps. These mutants also exhibited an exaggerated clumping phenotype in liquid media, which was complemented fully by a plasmid-encoded norR gene. Collectively, these results indicate that NorR is a multifunctional regulator, affecting cell surface properties as well as the expression of NorA and likely other multidrug resistance efflux pumps.

scholarly journals Removal of a Mig1p Binding Site Converts a MAL63 Constitutive Mutant Derived by Interchromosomal Gene Conversion to Glucose Insensitivity

Genetics ◽  
1996 ◽  
Vol 142 (1) ◽  
pp. 51-63 ◽  
Author(s):  
Jianfan Wang ◽  
Richard Needleman
Keyword(s):  
Binding Site ◽  
Gene Conversion ◽  
Glucose Repression ◽  
Maltose Permease ◽  
Glucose Sensitivity ◽  
Mal Genes ◽  
Chromosome Iii ◽  
Chromosome Ii ◽  
Multiple Amino Acid ◽  
Constitutive Mutant

Maltose fermenting strains of Saccharomyces cerevisiae have one or more complex loci called MAL. Each locus comprises at least three genes: MALx1 encodes maltose permease, MALx2 encodes maltase, and MALx3 encodes an activator of MALxl and MALx2 (x denotes one of five MAL loci, with x = 1, 2, 3, 4, or 6). The MAL43c allele is constitutive and relatively insensitive to glucose repression. To understand better this unique phenotype of MAL43c, we have isolated several MAL63c constitutive mutants from a MAL6 strain. All constitutive mutants remain glucose repressible, and all have multiple amino acid substitutions in the C-terminal region, now making this region of Mal63cp similar to that of Mal43cp. These changes have been generated by gene conversion, which transfers DNA from the telomeres of chromosome II and chromosome III or XVI to chromosome VIII (MAL6). The removal of a Mig1p binding site from the MAL63c promoter leads to a loss of glucose repression, imitating the phenotype of MAL43c. Conversely, addition of a Mig1p binding site to the promoter of MAL43c converts it to glucose sensitivity. Mig1p modulation of Mal63p and Ma143p expression therefore plays a substantial role in glucose repression of the MAL, genes.

scholarly journals Stimulation of yeast meiotic gene expression by the glucose-repressible protein kinase Rim15p.

1997 ◽  
Vol 17 (5) ◽  
pp. 2688-2697 ◽  
Author(s):  
S Vidan ◽  
A P Mitchell
Keyword(s):  
Gene Expression ◽  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Protein Kinases ◽  
Glucose Repression ◽  
Glucose Inhibition ◽  
Two Hybrid ◽  
Residue Polypeptide ◽  
Regulatory Sites ◽  
Stimulation Of

The Saccharomyces cerevisiae RIM15 gene was identified previously through a mutation that caused reduced ability to undergo meiosis. We report here an analysis of the cloned RIM15 gene, which specifies a 1,770-residue polypeptide with homology to serine/threonine protein kinases. Rim15p is most closely related to Schizosaccharomyces pombe cek1+. Analysis of epitope-tagged derivatives indicates that Rim15p has autophosphorylation activity. Deletion of RIM15 causes reduced expression of several early meiotic genes (IME2, SPO13, and HOP1) and of IME1, which specifies an activator of early meiotic genes. However, overexpression of IME1 does not permit full expression of early meiotic genes in a rim15delta mutant. Ime1p activates early meiotic genes through its interaction with Ume6p, and analysis of Rim15p-dependent regulatory sites at the IME2 promoter indicates that activation through Ume6p is defective. Two-hybrid interaction assays suggest that Ime1p-Ume6p interaction is diminished in a rim15 mutant. Glucose inhibits Ime1p-Ume6p interaction, and we find that Rim15p accumulation is repressed in glucose-grown cells. Thus, glucose repression of Rim15p may be responsible for glucose inhibition of Ime1p-Ume6p interaction.

scholarly journals Molecular characterization of myelin basic protein a (mbpa) gene from red-bellied pacu (Piaractus brachypomus)

2022 ◽  
Vol 20 (1) ◽  
Author(s):  
Juan Sebastian Cruz-Méndez ◽  
María Paula Herrera-Sánchez ◽  
Ángel Enrique Céspedes-Rubio ◽  
Iang Schroniltgen Rondón-Barragán
Keyword(s):  
Gene Expression ◽  
Brain Injury ◽  
Myelin Basic Protein ◽  
Molecular Characterization ◽  
Basic Protein ◽  
Protein A ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Regions ◽  
Disordered Regions

Abstract Background Myelin basic protein (MBP) is one of the most important structural components of the myelin sheaths in both central and peripheral nervous systems. MBP has several functions including organization of the myelin membranes, reorganization of the cytoskeleton during the myelination process, and interaction with the SH3 domain in signaling pathways. Likewise, MBP has been proposed as a marker of demyelination in traumatic brain injury and chemical exposure. Methods The aim of this study was to molecularly characterize the myelin basic protein a (mbpa) gene from the Colombian native fish, red-bellied pacu, Piaractus brachypomus. Bioinformatic tools were used to identify the phylogenetic relationships, physicochemical characteristics, exons, intrinsically disordered regions, and conserved domains of the protein. Gene expression was assessed by qPCR in three models corresponding to sublethal chlorpyrifos exposure, acute brain injury, and anesthesia experiments. Results mbpa complete open reading frame was identified with 414 nucleotides distributed in 7 exons that encode 137 amino acids. MBPa was recognized as belonging to the myelin basic protein family, closely related with orthologous proteins, and two intrinsically disordered regions were established within the sequence. Gene expression of mbpa was upregulated in the optic chiasm of the chlorpyrifos exposed fish in contrast to the control group. Conclusions The physicochemical computed features agree with the biological functions of MBP, and basal gene expression was according to the anatomical distribution in the tissues analyzed. This study is the first molecular characterization of mbpa from the native species Piaractus brachypomus.

scholarly journals Cloning and characterization of hELD/OSA1, a novel BRG1 interacting protein

2002 ◽  
Vol 364 (1) ◽  
pp. 255-264 ◽  
Author(s):  
Adam F.L. HURLSTONE ◽  
Ivan A. OLAVE ◽  
Nick BARKER ◽  
Mascha van NOORT ◽  
Hans CLEVERS
Keyword(s):  
Protein A ◽  
The Other ◽  
Dna Binding Domain ◽  
Related Protein ◽  
Related Gene ◽  
Human Homologue ◽  
Interacting Protein

A highly conserved multisubunit enzymic complex, SWI/SNF, participates in the regulation of eukaryote gene expression through its ability to remodel chromatin. While a single component of SWI/SNF, Swi2 or a related protein, can perform this function in vitro, the other components appear to modulate the activity and specificity of the complex in vivo. Here we describe the cloning of hELD/OSA1, a 189KDa human homologue of Drosophila Eld/Osa protein, a constituent of Drosophila SWI/SNF. By comparing conserved peptide sequences in Eld/Osa homologues we define three domains common to all family members. A putative DNA binding domain, or ARID (AT-rich DNA-interacting domain), may function in targetting SWI/SNF to chromatin. Two other domains unique to Eld/Osa proteins, EHD1 and EHD2, map to the C-teminus. We show that EHD2 mediates binding to Brahma-related gene 1 (BRG1), a human homologue of yeast Swi2. EHD1 and EHD2 also appear capable of interacting with each other. Using an antibody raised against EHD2 of hELD/OSA1, we detected Eld/Osa1 in endogenous SWI/SNF complexes derived from mouse brain.

scholarly journals Twenty-four–nucleotide siRNAs produce heritable trans-chromosomal methylation in F1 Arabidopsis hybrids

2016 ◽  
Vol 113 (44) ◽  
pp. E6895-E6902 ◽  
Author(s):  
Ian K. Greaves ◽  
Steven R. Eichten ◽  
Michael Groszmann ◽  
Aihua Wang ◽  
Hua Ying ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Epigenetic Reprogramming ◽  
The Other ◽  
F1 Hybrid ◽  
Methylation State ◽  
Independent Mechanism ◽  
Affect Gene Expression

Hybrid Arabidopsis plants undergo epigenetic reprogramming producing decreased levels of 24-nt siRNAs and altered patterns of DNA methylation that can affect gene expression. Driving the changes in methylation are the processes trans-chromosomal methylation (TCM) and trans-chromosomal demethylation (TCdM). In TCM/TCdM the methylation state of one allele is altered to resemble the other allele. We show that Pol IV-dependent sRNAs are required to establish TCM events. The changes in DNA methylation and the associated changes in sRNA levels in the F1 hybrid can be maintained in subsequent generations and affect hundreds of regions in the F2 epigenome. The inheritance of these altered epigenetic states varies in F2 individuals, resulting in individuals with genetically identical loci displaying different epigenetic states and gene expression profiles. The change in methylation at these regions is associated with the presence of sRNAs. Loci without any sRNA activity can have altered methylation states, suggesting that a sRNA-independent mechanism may also contribute to the altered methylation state of the F1 and F2 generations.

A very rapid in situ Kikuchi technique to determine relative crystal misorientation

1988 ◽  
Vol 46 ◽  
pp. 830-831
Author(s):  
J. I. Bennetch
Keyword(s):  
Electron Beam ◽  
Analytical Techniques ◽  
Superplastic Forming ◽  
The Other ◽  
Kikuchi Pattern ◽  
Kikuchi Line ◽  
Line Analysis

In a recent study of the superplastic forming (SPF) behavior of certain Al-Li-X alloys, the relative misorientation between adjacent (sub)grains proved to be an important parameter. It is well established that the most accurate way to determine misorientation across boundaries is by Kikuchi line analysis. However, the SPF study required the characterization of a large number of (sub)grains in each sample to be statistically meaningful, a very time-consuming task even for comparatively rapid Kikuchi analytical techniques.In order to circumvent this problem, an alternate, even more rapid in-situ Kikuchi technique was devised, eliminating the need for the developing of negatives and any subsequent measurements on photographic plates. All that is required is a double tilt low backlash goniometer capable of tilting ± 45° in one axis and ± 30° in the other axis. The procedure is as follows. While viewing the microscope screen, one merely tilts the specimen until a standard recognizable reference Kikuchi pattern is centered, making sure, at the same time, that the focused electron beam remains on the (sub)grain in question.

Rapid Isolation of High Molecular Weight Urokinase from Native Human Urine

1982 ◽  
Vol 47 (03) ◽  
pp. 197-202 ◽  
Author(s):  
Kurt Huber ◽  
Johannes Kirchheimer ◽  
Bernd R Binder
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Human Urine ◽  
Gel Filtration ◽  
Chain Structure ◽  
The Other ◽  
Single Chain ◽  
Apparent Homogeneity ◽  
Sequential Adsorption

SummaryUrokinase (UK) could be purified to apparent homogeneity starting from crude urine by sequential adsorption and elution of the enzyme to gelatine-Sepharose and agmatine-Sepharose followed by gel filtration on Sephadex G-150. The purified product exhibited characteristics of the high molecular weight urokinase (HMW-UK) but did contain two distinct entities, one of which exhibited a two chain structure as reported for the HMW-UK while the other one exhibited an apparent single chain structure. The purification described is rapid and simple and results in an enzyme with probably no major alterations. Yields are high enough to obtain purified enzymes for characterization of UK from individual donors.

Reparação óssea no implante dental

2020 ◽  
Vol 12 (45) ◽  
pp. 63-66
Author(s):  
Halim Nagem Filho ◽  
Reinaldo Francisco Maia ◽  
Reinaldo Missaka ◽  
Nasser Hussein Fares
Keyword(s):  
Gene Expression ◽  
Titanium Surface ◽  
Close Contact ◽  
The Other ◽  
Main Function ◽  
Indirect Interaction ◽  
M2 Macrophages ◽  
Activated Macrophages ◽  
M1 Macrophages ◽  
High Production

The osseointegration is the stable and functional union between the bone and a titanium surface. A new bone can be found on the surface of the implant about 1 week after its installation; the bone remodeling begins between 6 and 12 weeks and continues throughout life. After the implant insertion, depending on the energy of the surface, the plasma fluid immediately adheres, in close contact with the surface, promoting the adsorption of proteins and inducing the indirect interaction of the cells with the material. Macrophages are cells found in the tissues and originated from bone marrow monocytes. The M1 macrophages orchestrate the phagocytic phase in the inflammatory region and also produce inflammatory cytokines involved with the chronic inflammation and the cleaning of the wound and damaged tissues from bacteria. On the other hand, alternative-activated macrophages (M2) are activated by IL-10, the immune complex. Its main function consists on regulating negatively the inflammation through the secretion of the immunosuppressant IL-10. The M2 macrophages present involvement with the immunosuppression, besides having a low capacity for presenting antigens and high production of cytokines; these can be further divided into M2a, M2b, and M2c, based on the gene expression profile.

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