scholarly journals Response of Schizosaccharomyces pombe to Zinc Deficiency

2008 ◽  
Vol 7 (3) ◽  
pp. 454-464 ◽  
Author(s):  
Samantha J. Dainty ◽  
Ciara A. Kennedy ◽  
Stephen Watt ◽  
Jürg Bähler ◽  
Simon K. Whitehall
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Zinc Deficiency ◽  
Metal Ion ◽  
Cellular Response ◽  
Transcript Abundance ◽  
Zinc Uptake ◽  
Mrna Levels ◽  
Gene Encoding ◽  
Intracellular Zinc ◽  
Responsive Gene

ABSTRACT A component of the cellular response to zinc deficiency operates via control of transcript abundance. Therefore, microarray analysis was employed to identify Schizosaccharomyces pombe genes whose mRNA levels are regulated by intracellular zinc status. A set of 57 genes whose mRNA levels were substantially reduced in response to zinc deficiency was identified, while the mRNA levels of 63 genes were increased by this condition. In order to investigate the mechanisms that control these responses, a genetic screen was employed to identify mutants with defective zinc-responsive gene expression. Two strains (II-1 and V7) that were identified by this screen harbor mutations that are linked to zrt1 +, which encodes a putative Zrt/IRT-like protein (ZIP) zinc uptake transporter. Importantly, zrt1 + mRNA levels are increased in response to zinc deprivation, and cells lacking functional Zrt1 are highly impaired in their ability to proliferate at limiting zinc concentrations. Furthermore, zrt1 null cells were found to have severely reduced zinc contents, indicating that Zrt1 functions as a key regulator of intracellular zinc levels in fission yeast. The deletion of fet4 +, another zinc-responsive gene encoding a putative metal ion transporter, exacerbated the phenotypes associated with the loss of Zrt1, suggesting that Fet4 also plays a role in zinc uptake under limiting conditions.

scholarly journals Regulation and Activity of a Zinc Uptake Regulator, Zur, in Corynebacterium diphtheriae

2008 ◽  
Vol 191 (5) ◽  
pp. 1595-1603 ◽  
Author(s):  
Kelsy F. Smith ◽  
Lori A. Bibb ◽  
Michael P. Schmitt ◽  
Diana M. Oram
Keyword(s):  
Metal Ion ◽  
Ion Homeostasis ◽  
Transcriptional Regulator ◽  
Corynebacterium Diphtheriae ◽  
Zinc Uptake ◽  
Mrna Levels ◽  
Metal Ion Homeostasis ◽  
Expression Of Genes ◽  
Family Protein ◽  
Zinc Uptake Regulator

ABSTRACT Regulation of metal ion homeostasis is essential to bacterial cell survival, and in most species it is controlled by metal-dependent transcriptional regulators. In this study, we describe a Corynebacterium diphtheriae ferric uptake regulator-family protein, Zur, that controls expression of genes involved in zinc uptake. By measuring promoter activities and mRNA levels, we demonstrate that Zur represses transcription of three genes (zrg, cmrA, and troA) in zinc-replete conditions. All three of these genes have similarity to genes involved in zinc uptake. Transcription of zrg and cmrA was also shown to be regulated in response to iron and manganese, respectively, by mechanisms that are independent of Zur. We demonstrate that the activity of the zur promoter is slightly decreased under low zinc conditions in a process that is dependent on Zur itself. This regulation of zur transcription is distinctive and has not yet been described for any other zur. An adjacent gene, predicted to encode a metal-dependent transcriptional regulator in the ArsR/SmtB family, is transcribed from a separate promoter whose activity is unaffected by Zur. A C. diphtheriae zur mutant was more sensitive to peroxide stress, which suggests that zur has a role in protecting the bacterium from oxidative damage. Our studies provide the first evidence of a zinc specific transcriptional regulator in C. diphtheriae and give new insights into the intricate regulatory network responsible for regulating metal ion concentrations in this toxigenic human pathogen.

scholarly journals Facilitation of trace metal uptake in cells by inulin coating of metallic nanoparticles

2017 ◽  
Vol 4 (9) ◽  
pp. 170480 ◽  
Author(s):  
Esmeralda Santillán-Urquiza ◽  
Fernando Arteaga-Cardona ◽  
Cristina Torres-Duarte ◽  
Bryan Cole ◽  
Bing Wu ◽  
...  
Keyword(s):  
Metallic Nanoparticles ◽  
Cellular Response ◽  
Metal Uptake ◽  
Membrane Integrity ◽  
Zinc Uptake ◽  
Proper Function ◽  
Intracellular Zinc ◽  
Biochemical Processes ◽  
Different Sources

Trace elements such as zinc and iron are essential for the proper function of biochemical processes, and their uptake and bioavailability are dependent on their chemical form. Supplementation of trace metals through nanostructured materials is a new field, but its application raises concerns regarding their toxicity. Here, we compared the intracellular zinc uptake of different sources of zinc: zinc sulfate, and ZnO and core-shell α-Fe 2 O 3 @ZnO nanoparticles, coated or uncoated with inulin, an edible and biocompatible polysaccharide. Using mussel haemocytes, a well-known model system to assess nanomaterial toxicity, we simultaneously assessed zinc accumulation and multiple cellular response endpoints. We found that intracellular zinc uptake was strongly enhanced by inulin coating, in comparison to the uncoated nanoparticles, while no significant effects on cell death, cell viability, mitochondrial membrane integrity, production of reactive oxygen species or lysosome abundance were observed at concentrations up to 20 ppm. Since no significant increments in toxicity were observed, the coated nanomaterials may be useful to increase in vivo zinc uptake for nutritional applications.

scholarly journals The Schizosaccharomyces pombe cho1+ Gene Encodes a Phospholipid Methyltransferase

Genetics ◽  
1998 ◽  
Vol 150 (2) ◽  
pp. 553-562
Author(s):  
Margaret I Kanipes ◽  
John E Hill ◽  
Susan A Henry
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Sequence Analysis ◽  
Schizosaccharomyces Pombe ◽  
Gene Disruption ◽  
Structure And Function ◽  
Biosynthetic Enzyme ◽  
Gene Encoding ◽  
Complementation Groups ◽  
Eukaryotic Organisms ◽  
And Function

Abstract The isolation of mutants of Schizosaccharomyces pombe defective in the synthesis of phosphatidylcholine via the methylation of phosphatidylethanolamine is reported. These mutants are choline auxotrophs and fall into two unlinked complementation groups, cho1 and cho2. We also report the analysis of the cho1+ gene, the first structural gene encoding a phospholipid biosynthetic enzyme from S. pombe to be cloned and characterized. The cho1+ gene disruption mutant (cho1Δ) is viable if choline is supplied and resembles the cho1 mutants isolated after mutagenesis. Sequence analysis of the cho1+ gene indicates that it encodes a protein closely related to phospholipid methyltransferases from Saccharomyces cerevisiae and rat. Phospholipid methyltransferases encoded by a rat liver cDNA and the S. cerevisiae OPI3 gene are both able to complement the choline auxotrophy of the S. pombe cho1 mutants. These results suggest that both the structure and function of the phospholipid N-methyltransferases are broadly conserved among eukaryotic organisms.

Metallothionein gene expression and secretion in white adipose tissue

2000 ◽  
Vol 279 (6) ◽  
pp. R2329-R2335 ◽  
Author(s):  
Paul Trayhurn ◽  
Jacqueline S. Duncan ◽  
Anne M. Wood ◽  
John H. Beattie
Keyword(s):  
Gene Expression ◽  
Molecular Weight ◽  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Stromal Vascular Fraction ◽  
Low Molecular Weight ◽  
Secretory Product ◽  
Mrna Levels ◽  
Gene Encoding ◽  
Adrenoceptor Agonist

White adipose tissue (WAT) has been examined to determine whether the gene encoding metallothionein (MT), a low-molecular-weight stress response protein, is expressed in the tissue and whether MT may be a secretory product of adipocytes. The MT-1 gene was expressed in epididymal WAT, with MT-1 mRNA levels being similar in lean and obese ( ob/ ob) mice. MT-1 mRNA was found in each of the main adipose tissue sites (epididymal, perirenal, omental, subcutaneous), and there was no major difference between depots. Separation of adipocytes from the stromal-vascular fraction of WAT indicated that the MT gene (MT-1 and MT-2) was expressed in adipocytes themselves. Treatment of mice with zinc had no effect on MT-1 mRNA levels in WAT, despite strong induction of MT-1 expression in the liver. MT-1 gene expression in WAT was also unaltered by fasting or norepinephrine. However, administration of a β3-adrenoceptor agonist, BRL-35153A, led to a significant increase in MT-1 mRNA. On differentiation of fibroblastic preadipocytes to adipocytes in primary culture, MT was detected in the medium, suggesting that the protein may be secreted from WAT. It is concluded that WAT may be a significant site of MT production; within adipocytes, MT could play an antioxidant role in protecting fatty acids from damage.

scholarly journals Granulosal and thecal expression of bone morphogenetic protein- and activin-binding protein mRNA transcripts during bovine follicle development and factors modulating their expression in vitro

Reproduction ◽  
2011 ◽  
Vol 142 (4) ◽  
pp. 581-591 ◽  
Author(s):  
Claire Glister ◽  
Leanne Satchell ◽  
Phil G Knight
Keyword(s):  
Bone Morphogenetic Proteins ◽  
Transforming Growth Factor ◽  
Ex Vivo ◽  
Mrna Level ◽  
Transcript Abundance ◽  
Transforming Growth Factor Β ◽  
Follicle Development ◽  
Mrna Levels ◽  
Theca Interna

Evidence supports local roles for transforming growth factor β superfamily members including activins and bone morphogenetic proteins (BMP) in follicle development. Access of these ligands to signalling receptors is likely modulated by extracellular binding proteins (BP). In this study, we comparedex vivoexpression of four BPs (chordin, gremlin, noggin and follistatin) in granulosal (GC) and theca interna (TC) compartments of developing bovine antral follicles (1–18 mm). Effects of FSH and IGF on BMP and BP expression by cultured GC, and effects of LH and BMPs on BP expression by cultured TC were also examined. Follicular expression of all four BP transcripts was higher in GC than TC compartments (P<0.001) a finding confirmed by immunohistochemistry. Follicle category affected (P<0.01) gremlin and follistatin mRNA abundance, with a significant cell-type×follicle category interaction for chordin, follistatin and noggin. Noggin transcript abundance was lower (P<0.05) in GC of large ‘E-active’ than ‘E-inactive’ follicles while follistatin mRNA level was higher (P<0.01). FSH enhanced CYP19, FSHR, INHBA and follistatin by GC without affecting BMP or BMP–BP expression. IGF increased CYP19 and follistatin, reduced BMP4, noggin and gremlin but did not affect chordin orFSHRmRNA levels. LH increased TC androgen secretion but had no effect on BMP or BP expression. BMPs uniformly suppressed TC androgen production whilst increasing chordin, noggin and gremlin mRNA levels up to 20-fold (P<0.01). These findings support the hypothesis that extracellular BP, mostly from GC, contribute to the regulation of intrafollicular BMP/activin signalling. Enhancement of thecal BP expression by BMP implies an autoregulatory feedback role to prevent excessive signalling.

scholarly journals Functional Analysis of the Bacillus subtilis Zur Regulon

2002 ◽  
Vol 184 (23) ◽  
pp. 6508-6514 ◽  
Author(s):  
Ahmed Gaballa ◽  
Tao Wang ◽  
Rick W. Ye ◽  
John D. Helmann
Keyword(s):  
Bacillus Subtilis ◽  
Metal Ion ◽  
Dna Microarrays ◽  
Optimal Growth ◽  
Zinc Uptake ◽  
Uptake System ◽  
Mobility Shift ◽  
Transport Pathway ◽  
Dnase I Footprinting ◽  
Transporter Family

ABSTRACT The Bacillus subtilis zinc uptake repressor (Zur) regulates genes involved in zinc uptake. We have used DNA microarrays to identify genes that are derepressed in a zur mutant. In addition to members of the two previously identified Zur-regulated operons (yciC and ycdHI-yceA), we identified two other genes, yciA and yciB, as targets of Zur regulation. Electrophoretic mobility shift experiments demonstrated that all three operons are direct targets of Zur regulation. Zur binds to an ∼28-bp operator upstream of the yciA gene, as judged by DNase I footprinting, and similar operator sites are found preceding each of the previously described target operons, yciC and ycdHI-yceA. Analysis of a yciA-lacZ fusion indicates that this operon is induced under zinc starvation conditions and derepressed in the zur mutant. Phenotypic analyses suggest that the YciA, YciB, and YciC proteins may function as part of the same Zn(II) transport pathway. Mutation of yciA or yciC, singly or in combination, had little effect on growth of the wild-type strain but significantly impaired the growth of the ycdH mutant under conditions of zinc limitation. Since the YciA, YciB, and YciC proteins are not obviously related to any known transporter family, they may define a new class of metal ion uptake system. Mutant strains lacking all three identified zinc uptake systems (yciABC, ycdHI-yceA, and zosA) are dependent on micromolar levels of added zinc for optimal growth.

Cyclic AMP analogs and retinoic acid influence the expression of retinoic acid receptor alpha, beta, and gamma mRNAs in F9 teratocarcinoma cells

1990 ◽  
Vol 10 (1) ◽  
pp. 391-396
Author(s):  
L Hu ◽  
L J Gudas
Keyword(s):  
Retinoic Acid ◽  
Steady State ◽  
Cyclic Amp ◽  
Cellular Response ◽  
Retinoic Acid Receptor ◽  
Mrna Level ◽  
Mrna Levels ◽  
Protein Synthesis Inhibitors ◽  
Receptor Alpha ◽  
F9 Teratocarcinoma

Retinoic acid (RA) receptor alpha (RAR alpha) and RAR gamma steady-state mRNA levels remained relatively constant over time after the addition of RA to F9 teratocarcinoma stem cells. In contrast, the steady-state RAR beta mRNA level started to increase within 12 h after the addition of RA and reached a 20-fold-higher level by 48 h. This RA-associated RAR beta mRNA increase was not prevented by protein synthesis inhibitors but was prevented by the addition of cyclic AMP analogs. In the presence of RA, cyclic AMP analogs also greatly reduced the RAR alpha and RAR gamma mRNA levels, even though cyclic AMP analogs alone did not alter these mRNA levels. The addition of either RA or RA plus cyclic AMP analogs did not result in changes in the three RAR mRNA half-lives. These results suggest that agents which elevate the internal cyclic AMP concentration may also affect the cellular response to RA by altering the expression of the RARs.

Control of mRNA turnover as a mechanism of glucose repression in Saccharomyces cerevisiae

1992 ◽  
Vol 12 (7) ◽  
pp. 2941-2948
Author(s):  
A Lombardo ◽  
G P Cereghino ◽  
I E Scheffler
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Succinate Dehydrogenase ◽  
Half Life ◽  
Glucose Repression ◽  
Promoter Sequence ◽  
Regulatory Elements ◽  
Mrna Levels ◽  
Protein Subunit ◽  
Gene Encoding ◽  
Regulatory Complex

We have examined the expression of the gene encoding the iron-protein subunit (Ip) of succinate dehydrogenase in Saccharomyces cerevisiae. The gene had been cloned by us and shown to be subject to glucose regulation (A. Lombardo, K. Carine, and I. E. Scheffler, J. Biol. Chem. 265:10419-10423, 1990). We discovered that a significant part of the regulation of the Ip mRNA levels by glucose involves the regulation of the turnover rate of this mRNA. In the presence of glucose, the half-life appears to be less than 5 min, while in glycerol medium, the half-life is greater than 60 min. The gene is also regulated transcriptionally by glucose. The upstream promoter sequence appeared to have four regulatory elements with consensus sequences shown to be responsible for the interaction with the HAP2/3/4 regulatory complex. A deletion analysis has shown that the two distal elements are redundant. These measurements were carried out by Northern (RNA) analyses of Ip mRNA transcripts as well as by assays of beta-galactosidase activity in cells carrying constructs of the Ip promoter linked to the lacZ coding sequence. These observations on the regulation of mRNA stability were also extended to the mRNA of the flavoprotein subunit of succinate dehydrogenase and in some experiments of iso-1-cytochrome c.

Autoregulated Expression of Schizosaccharomyces pombe Meiosis-Specific Transcription Factor Mei4 and a Genome-Wide Search for Its Target Genes

Genetics ◽  
2000 ◽  
Vol 154 (4) ◽  
pp. 1497-1508 ◽  
Author(s):  
Hiroko Abe ◽  
Chikashi Shimoda
Keyword(s):  
Transcription Factor ◽  
Schizosaccharomyces Pombe ◽  
Target Genes ◽  
Northern Blotting ◽  
Forkhead Transcription Factor ◽  
Gene Encoding ◽  
Putative Promoter Region ◽  
Cis Acting ◽  
A Genome ◽  
Genome Wide Search

Abstract The Schizosaccharomyces pombe mei4+ gene encoding a forkhead transcription factor is necessary for the progression of meiosis and sporulation. We searched for novel meiotic genes, the expression of which is dependent on Mei4p, since only the spo6+ gene has been assigned to its targets. Six known genes responsible for meiotic recombination were examined by Northern blotting, but none were Mei4 dependent for transcription. We determined the important cis-acting element, designated FLEX, to which Mei4p can bind. The S. pombe genome sequence database (The Sanger Centre, UK) was scanned for the central core heptamer and its flanking 3′ sequence of FLEX composed of 17 nucleotides, and 10 candidate targets of Mei4 were selected. These contained a FLEX-like sequence in the 5′ upstream nontranslatable region within 1 kb of the initiation codon. Northern blotting confirmed that 9 of them, named mde1+ to mde9+, were transcriptionally induced during meiosis and were dependent on mei4+. Most mde genes have not been genetically defined yet, except for mde9+, which is identical to spn5+, which encodes one of the septin family of proteins. mde3+ and a related gene pit1+ encode proteins related to Saccharomyces cerevisiae Ime2. The double disruptant frequently produced asci having an abnormal number and size of spores, although it completed meiosis. We also found that the forkhead DNA-binding domain of Mei4p binds to the FLEX-like element in the putative promoter region of mei4 and that the maximum induction level of mei4 mRNA required functional mei4 activity. Furthermore, expression of a reporter gene driven by the authentic mei4 promoter was induced in vegetative cells by ectopic overproduction of Mei4p. These results suggest that mei4 transcription is positively autoregulated.

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