Intracellular Iron-Binding Macromolecules in HeLa Cells

ABSTRACT RyhB is a noncoding RNA regulated by the Fur repressor. It has previously been shown to cause the rapid degradation of a number of mRNAs that encode proteins that utilize iron. Here we examine the effect of ectopic RyhB production on global gene expression by microarray analysis. Many of the previously identified targets were found, as well as other mRNAs encoding iron-binding proteins, bringing the total number of regulated operons to at least 18, encoding 56 genes. The two major operons involved in Fe-S cluster assembly showed different behavior; the isc operon appears to be a direct target of RyhB action, while the suf operon does not. This is consistent with previous findings suggesting that the suf genes but not the isc genes are important for Fe-S cluster synthesis under iron-limiting conditions, presumably for essential iron-binding proteins. In addition, we observed repression of Fur-regulated genes upon RyhB expression, interpreted as due to intracellular iron sparing resulting from reduced synthesis of iron-binding proteins. Our results demonstrate the broad effects of a single noncoding RNA on iron homeostasis.

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Intracellular Iron Binding and Antioxidant Activity of Phytochelators

Biological Trace Element Research ◽

10.1007/s12011-021-02965-y ◽

2021 ◽

Author(s):

Fredson Torres Silva ◽

Breno Pannia Espósito

Keyword(s):

Antioxidant Activity ◽

Iron Binding ◽

Intracellular Iron

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Heat Shock Protein 90 Recognized as an Iron-Binding Protein Associated with the Plasma Membrane of HeLa Cells

Cellular Physiology and Biochemistry ◽

10.1159/000076925 ◽

2004 ◽

Vol 14 (1-2) ◽

pp. 41-46 ◽

Cited By ~ 11

Author(s):

Jan Kovár ◽

Hana Stýbrová ◽

Petr Novák ◽

Marie Ehrlichová ◽

Jaroslav Truksa ◽

...

Keyword(s):

Plasma Membrane ◽

Heat Shock ◽

Heat Shock Protein ◽

Hela Cells ◽

Binding Protein ◽

Heat Shock Protein 90 ◽

Iron Binding ◽

Iron Binding Protein

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Characterization of iron binding in IscA, an ancient iron-sulphur cluster assembly protein

Biochemical Journal ◽

10.1042/bj20031702 ◽

2004 ◽

Vol 379 (2) ◽

pp. 433-440 ◽

Cited By ~ 83

Author(s):

Huangen DING ◽

Robert J. CLARK

Keyword(s):

Association Constant ◽

Binding Protein ◽

Iron Binding ◽

Cluster Assembly ◽

Intracellular Iron ◽

Ancient Iron ◽

Iron Binding Protein ◽

Redox Centre

Iron–sulphur clusters are one of the most common types of redox centre in biology. At least six proteins (IscS, IscU, IscA, HscB, HscA and ferredoxin) have been identified as being essential for the biogenesis of iron–sulphur proteins in bacteria. It has been shown that IscS is a cysteine desulphurase that provides sulphur for iron–sulphur clusters, and that IscU is a scaffold for the IscS-mediated assembly of iron–sulphur clusters. The iron donor for iron–sulphur clusters, however, remains elusive. Here we show that IscA is an iron binding protein with an apparent iron association constant of 3.0×1019 M−1, and that iron-loaded IscA can provide iron for the assembly of transient iron–sulphur clusters in IscU in the presence of IscS and l-cysteine in vitro. The results suggest that IscA is capable of recruiting intracellular iron and delivering iron for iron–sulphur clusters in proteins.

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Screens, iron, and leukemia

Blood ◽

10.1182/blood-2009-08-234161 ◽

2009 ◽

Vol 114 (14) ◽

pp. 2857-2858 ◽

Cited By ~ 8

Author(s):

Richard M. Stone ◽

Daniel J. DeAngelo

Keyword(s):

Hela Cells ◽

Antileukemic Activity ◽

Intracellular Iron ◽

Down Regulation ◽

Survivin Promoter

In this issue of Blood, Eberhard and colleagues screen a large library of off-patent agents for down-regulation of the survivin promoter in HeLa cells. Their most specific “hit” was ciclopirox, formerly developed as an antifungal, which was found to have preclinical antileukemic activity possibly via depletion of intracellular iron.

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Cytochemistry of colloidal iron binding to the surface of hela cells and human erythrocytes

Histochemistry ◽

10.1007/bf00489718 ◽

1976 ◽

Vol 48 (1) ◽

pp. 71-80 ◽

Cited By ~ 6

Author(s):

M. Mareel ◽

C. Dragonetti ◽

M. C. Van Peteghem

Keyword(s):

Hela Cells ◽

Human Erythrocytes ◽

Iron Binding ◽

Colloidal Iron

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Colloidal iron binding to the surface of HeLa cells, spreading in monolayer culture

Histochemistry ◽

10.1007/bf00509245 ◽

1977 ◽

Vol 53 (4) ◽

pp. 285-290 ◽

Cited By ~ 2

Author(s):

M. C. Van Peteghem ◽

M. Mareel ◽

C. Dragonetti

Keyword(s):

Hela Cells ◽

Monolayer Culture ◽

Iron Binding ◽

Colloidal Iron

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Platinum Compounds as Stains for Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051165 ◽

1974 ◽

Vol 32 ◽

pp. 230-231

Author(s):

S. K. Aggarwal ◽

P. McAllister ◽

R. W. Wagner ◽

B. Rosenberg

Keyword(s):

Electron Microscopy ◽

Hela Cells ◽

Uranyl Acetate ◽

Sarcoma 180 ◽

Platinum Compounds ◽

Kb Cells ◽

En Bloc ◽

Human Lymphoma ◽

Ultrathin Sections ◽

Blue Coloration

Uranyl acetate has been used as an electron stain for en bloc staining as well as for staining ultrathin sections in conjunction with various lead stains (Fig. 1). Present studies reveal that various platinum compounds also show promise as electron stains. Certain platinum compounds have been shown to be effective anti-tumor agents. Of particular interest are the compounds with either uracil or thymine as one of the ligands (cis-Pt(II)-uracil; cis-Pt(II)-thymine). These compounds are amorphous, highly soluble in water and often exhibit an intense blue coloration. These compounds show enough electron density to be used as stains for electron microscopy. Most of the studies are based on various cell lines (human AV, cells, human lymphoma cells, KB cells, Sarcoma-180 ascites cells, chick fibroblasts and HeLa cells) while studies on tissue blocks are in progress.

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Electron Microscopy of Mycoplasma Pneumoniae

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100065341 ◽

1971 ◽

Vol 29 ◽

pp. 258-259 ◽

Cited By ~ 1

Author(s):

E. S. Boatman ◽

G. E. Kenny

Keyword(s):

Electron Microscopy ◽

Light Microscopy ◽

Growth Phase ◽

Hela Cells ◽

Sulfonic Acid ◽

Gamma Globulin ◽

Horse Serum ◽

Morphological Aspects ◽

The Family

Information concerning the morphology and replication of organism of the family Mycoplasmataceae remains, despite over 70 years of study, highly controversial. Due to their small size observations by light microscopy have not been rewarding. Furthermore, not only are these organisms extremely pleomorphic but their morphology also changes according to growth phase. This study deals with the morphological aspects of M. pneumoniae strain 3546 in relation to growth, interaction with HeLa cells and possible mechanisms of replication.The organisms were grown aerobically at 37°C in a soy peptone yeast dialysate medium supplemented with 12% gamma-globulin free horse serum. The medium was buffered at pH 7.3 with TES [N-tris (hyroxymethyl) methyl-2-aminoethane sulfonic acid] at 10mM concentration. The inoculum, an actively growing culture, was filtered through a 0.5 μm polycarbonate “nuclepore” filter to prevent transfer of all but the smallest aggregates. Growth was assessed at specific periods by colony counts and 800 ml samples of organisms were fixed in situ with 2.5% glutaraldehyde for 3 hrs. at 4°C. Washed cells for sectioning were post-fixed in 0.8% OSO4 in veronal-acetate buffer pH 6.1 for 1 hr. at 21°C. HeLa cells were infected with a filtered inoculum of M. pneumoniae and incubated for 9 days in Leighton tubes with coverslips. The cells were then removed and processed for electron microscopy.

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Use of Uranium-Labeled Antibodies for Electron Microscopic Localization of Various Antigens in Mammalian Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100060696 ◽

1967 ◽

Vol 25 ◽

pp. 136-137

Author(s):

J. P. Petrali ◽

E. J. Donati ◽

L. A. Sternberger

Keyword(s):

Endoplasmic Reticulum ◽

Hela Cells ◽

Mammalian Cells ◽

Specific Antiserum ◽

Electron Microscopic ◽

E Coli ◽

Cytoplasmic Membranes ◽

Viral Progeny ◽

Ultrathin Sections ◽

Electron Microscopic Localization

Specific contrast is conferred to subcellular antigen by applying purified antibodies, exhaustively labeled with uranium under immunospecific protection, to ultrathin sections. Use of Seligman’s principle of bridging osmium to metal via thiocarbohydrazide (TCH) intensifies specific contrast. Ultrathin sections of osmium-fixed materials were stained on the grid by application of 1) thiosemicarbazide (TSC), 2) unlabeled specific antiserum, 3) uranium-labeled anti-antibody and 4) TCH followed by reosmication. Antigens to be localized consisted of vaccinia antigen in infected HeLa cells, lysozyme in monocytes of patients with monocytic or monomyelocytic leukemia, and fibrinogen in the platelets of these leukemic patients. Control sections were stained with non-specific antiserum (E. coli).In the vaccinia-HeLa system, antigen was localized from 1 to 3 hours following infection, and was confined to degrading virus, the inner walls of numerous organelles, and other structures in cytoplasmic foci. Surrounding architecture and cellular mitochondria were unstained. 8 to 14 hours after infection, antigen was localized on the outer walls of the viral progeny, on cytoplasmic membranes, and free in the cytoplasm. Staining of endoplasmic reticulum was intense and focal early, and weak and diffuse late in infection.

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