Succinate Dehydrogenase b mRNA of Drosophila melanogaster Has a Functional Iron-responsive Element in Its 5′-Untranslated Region

Kohler, Stefan A.; Henderson, Beric R.; Kühn, Lukas C.

doi:10.1074/jbc.270.51.30781

Cited by 126 publications

(87 citation statements)

References 36 publications

(59 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…fruitfly were estimated to be 95Ϫ100 kDa, which are similar to Even though no full-length clones are available, several lines that of mammalian IRP-1 [26,27]. However, the migration of of evidence suggest that the presented IRP represent the lamprey the IRE/IRP complex of rainbow trout differed from those of homologues of mammalian IRP-1 and IRP-2.…”

Section: Methodsmentioning

confidence: 70%

Regulation of iron metabolism in the sanguivore lamprey Lampetra fluviatilis

Andersen¹,

Pantopoulos²,

Kao

et al. 1998

European Journal of Biochemistry

View full text Add to dashboard Cite

Two ferritin cDNAs were cloned from the liver and spinal cord of the sanguivore lamprey Lampetra fluviatilis, an extant representative of the ancient agnathan (jawless) stage in vertebrate evolution. The deduced proteins of 20.2 kDa (H-subunit) and 20.1 kDa (M-subunit) display 73% sequence identity, and both contain the ferroxidase center characteristic of animal H-ferritin. A highly conserved iron-responsive element (IRE) was identified in the 5′ untranslated region of lamprey H-ferritin. Lamprey ferritin IRE forms a specific complex with crude lamprey and rat liver extracts, and with recombinant human ironregulatory protein (IRP-1) in an electrophoretic mobility shift assay. Furthermore, lamprey ferritin IRE competes with labeled human ferritin IRE for binding to IRP in lamprey and mammalian extracts. Two liver cDNA sequences encoding 323 residues and 101 residues of two genetically distinct lamprey IRP were amplified by PCR. Lamprey IRP-1 and IRP-2, which are 72% identical, display about 74% sequence identity to their presumed homologues in mammals. Northern blot analysis shows that two IRP transcripts of 3.6 kb and 5.8 kb are expressed in lamprey liver. Given the ancient lineage of lampreys, the results indicate that the IRE/IRP regulatory system has remained highly conserved during the evolution of vertebrates.Keywords : ferritin; iron-responsive element ; iron-regulatory protein; iron; lamprey.Ferritin plays a crucial role in the iron homeostasis of all interactions of cytosolic iron-regulatory protein (IRP)-1 and IRP-2 with the iron-responsive element (IRE), a structural motif living organisms by storing the metal in a readily available but non-toxic form. The hollow, symmetrical ferritin sphere enclos-within the 5′ untranslated region (UTR) of ferritin mRNAs [9,10]. When cells are deprived of iron, IRP-1 and IRP-2 have high ing the core of Fe 3ϩ is composed of 24 subunits. Animal ferritin consists of at least two types of subunits, which are encoded by affinity for IRE. Upon iron loading, IRP-1 is converted into a cytoplasmic aconitase with no IRE-binding activity [11Ϫ13], separate genes [1]. Whereas the H (heavy)-subunit contains a ferroxidase center involved in the oxidation of Fe 2ϩ , the L while IRP-2 is proteolytically degraded [14,15]. IRP have been cloned from several mammals [16Ϫ19], and chicken [20], and (light)-subunit is responsible for the formation of the iron core [2,3]. In bullfrog (Rana catespiana) and salmon (Salmo salar) the formation of IRE/IRP complexes has been studied extensively in mammals [21]. IRE motifs have also been identified in a third ferritin subunit, named M (middle)-subunit, was reported, ferritin mRNAs of lower vertebrates and invertebrates [5, 22Ϫ which showed great differences in sequence and tissue specific-25], and IRE/IRP interactions have been documented in frog ity compared with the H and L-subunits [4,5]. In comparison, (Xenopus laevis), rainbow trout and fruitfly (Drosophila melanothree similar, but genetic distinct ferritin H-isoforms were idengaster) [26Ϫ28]....

show abstract

Section: Methodsmentioning

confidence: 70%

Regulation of iron metabolism in the sanguivore lamprey Lampetra fluviatilis

Andersen¹,

Pantopoulos²,

Kao

et al. 1998

European Journal of Biochemistry

View full text Add to dashboard Cite

show abstract

“…Subsequent studies added further examples of cellular mRNAs that appear to obey the position effect (15,32) and also uncovered possible exceptions (15,23 [see below]). The mechanism by which cap-proximal IRE-IRP complexes regulate translation initiation is increasingly well understood.…”

Section: Discussionmentioning

confidence: 99%

“…An expanding number of mRNAs have been found to be translationally regulated by the IRE-IRP system (15,17,23). In mammalian cells, all of the examples that have been identified to date are regulated by cap-proximal IREs located Ͻ50 nucleotides downstream from the cap structure.…”

Section: Discussionmentioning

confidence: 99%

“…No such observation has been made with WGE, where moderately stable structures have been shown not to inhibit the progression of the translational machinery (26). While neither yeast nor plants appear to regulate their iron metabolism by the IRE-IRP system, the succinate dehydrogenase (Ip subunit) mRNA from Drosophila melanogaster was found to be translationally regulated by IRP (15,23). Dependent on the transcription start site, the IRE in this mRNA is located in either a cap-proximal or a cap-distal position.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Ribosomal Pausing and Scanning Arrest as Mechanisms of Translational Regulation from Cap-Distal Iron-Responsive Elements

Paraskeva

Gray

Schläger

et al. 1999

Molecular and Cellular Biology

View full text Add to dashboard Cite

Iron regulatory protein 1 (IRP-1) binding to an iron-responsive element (IRE) located close to the cap structure of mRNAs represses translation by precluding the recruitment of the small ribosomal subunit to these mRNAs. This mechanism is position dependent; reporter mRNAs bearing IREs located further downstream exhibit diminished translational control in transfected mammalian cells. To investigate the underlying mechanism, we have recapitulated this position effect in a rabbit reticulocyte cell-free translation system. We show that the recruitment of the 43S preinitiation complex to the mRNA is unaffected when IRP-1 is bound to a cap-distal IRE. Following 43S complex recruitment, the translation initiation apparatus appears to stall, before linearly progressing to the initiation codon. The slow passive dissociation rate of IRP-1 from the cap-distal IRE suggests that the mammalian translation apparatus plays an active role in overcoming the cap-distal IRE-IRP-1 complex. In contrast, cap-distal IRE-IRP-1 complexes efficiently repress translation in wheat germ and yeast translation extracts. Since inhibition occurs subsequent to 43S complex recruitment, an efficient arrest of productive scanning may represent a second mechanism by which RNA-protein interactions within the 5 untranslated region of an mRNA can regulate translation. In contrast to initiating ribosomes, elongating ribosomes from mammal, plant, and yeast cells are unaffected by IRE-IRP-1 complexes positioned within the open reading frame. These data shed light on a characteristic aspect of the IRE-IRP regulatory system and uncover properties of the initiation and elongation translation apparatus of eukaryotic cells.The regulation of iron metabolism by the iron-responsive element (IRE)-iron regulatory protein (IRP) system represents an intensively studied example of translational control in higher eukaryotes. Several mRNAs encoding proteins involved in cellular iron metabolism harbor an IRE at a cap-proximal position of their 5Ј untranslated regions (UTRs). The IRE is specifically recognized by IRP-1 and IRP-2, which bind to and repress the translation of IRE-containing mRNAs both in vivo and in vitro (17,39). Translational control by specific mRNAprotein interactions is commonly enacted at the level of translation initiation (e.g., caudal [6, 38], 15-lipoxygenase [35, 36], and oskar [22,43]). IRP binding to the IRE of ferritin mRNAs affects an early step of translation initiation: it prevents the recruitment of the 43S translation preinitiation complex (which includes the small ribosomal subunit) (13, 33). Transfection studies using mammalian tissue culture cells revealed a characteristic feature of this IRE-IRP regulatory mechanism: for IRP binding to efficiently block translation, the IRE must be located within Ͻ60 nucleotides from the m 7 GpppN-cap structure of the mRNA (9, 10). An IRE placed Ͼ60 nucleotides downstream from the cap structure mediates only partial translational inhibition by IRP binding. In keeping with this position effect, the cap-...

show abstract

“…The iron-induced decrease in IRP-1 binding activity occurs through a switch between apoprotein (high affinity) and [4Fe-4S] forms (low affinity) without changes in IRP-1 levels (18), whereas the decrease in IRP-2 binding activity is due to iron-induced IRP-2 proteolysis (19,20). IREs are also present on the 5Ј-untranslated regions of erythroid 5-aminolevulinate synthase (21) and mitochondrial aconitase (22) and on mitochondrial succinate dehydrogenase subunit b in Drosophila melanogaster (23). In addition to iron, nitric oxide (24 -26), oxidative stress (27,28), and ascorbic acid (29) have also been shown to regulate IRP binding to the IREs (reviewed in Ref.…”

mentioning

confidence: 99%

Resistance to the Antitumor Agent Gallium Nitrate in Human Leukemic Cells Is Associated with Decreased Gallium/Iron Uptake, Increased Activity of Iron Regulatory Protein-1, and Decreased Ferritin Production

Chitambar

Wereley

1997

Journal of Biological Chemistry

View full text Add to dashboard Cite

The mechanism of drug resistance to gallium nitrate is not known. Since gallium can be incorporated into ferritin, an iron storage protein that protects cells from iron toxicity, we investigated whether ferritin expression was altered in gallium-resistant (R) CCRF-CEM cells. We found that the ferritin content of R cells was decreased, while heavy chain ferritin mRNA levels and iron regulatory protein-1 (IRP-1) RNA binding activity were increased. IRP-1 protein levels were similar in gallium-sensitive (S) and R cells, indicating that R cells contain a greater proportion of IRP-1 in a high affinity mRNA binding state. 59 Fe uptake and transferrin receptor expression were decreased in R cells. In both S and R cells, gallium inhibited cellular 59 Fe uptake, increased ferritin mRNA and protein, and decreased IRP-1 binding activity. Gallium uptake by R cells was markedly diminished; however, the sensitivity of R cells to gallium could be restored by increasing their uptake of gallium with excess transferrin. Our results suggest that R cells have developed resistance to gallium by down-regulating their uptake of gallium. In parallel, iron uptake by R cells is also decreased, leading to changes in iron homeostasis. Furthermore, since gallium has divergent effects on iron uptake and ferritin synthesis, its action may also include a direct effect on ferritin mRNA induction and IRP-1 activity.Gallium nitrate, a group IIIa metal salt with antineoplastic activity (1), is currently undergoing evaluation as a chemotherapeutic agent. A number of clinical studies have shown gallium to be effective in the treatment of lymphoma and bladder cancer (2-4). Although gallium is in clinical use, information regarding its action at the cellular and molecular levels is largely incomplete. It has been known for some time that gallium resembles iron in certain respects. Gallium binds avidly to the iron transport protein Tf 1 (5) and is incorporated into cells by Tf receptor-dependent and -independent transport systems (6 -8). Furthermore, we have shown that gallium inhibits the growth of several leukemic cell lines by inhibiting cellular iron uptake and by blocking the activity of ribonucleotide reductase (9 -11).Iron taken up by cells is stored in ferritin, a high molecular weight protein composed of 24 subunits of H and L chains (12). Ferritin sequesters excess intracellular iron and protects cells from the toxicity of iron overload. An increase in the delivery of iron to cells therefore serves as a powerful stimulus for ferritin synthesis. It is now established that iron-dependent ferritin and transferrin receptor gene expression is regulated by the binding of two iron regulatory proteins (IRPs), IRP-1 and IRP-2, to sequences termed iron-responsive elements (IREs) present at the 5Ј-untranslated region of ferritin mRNA and the 3Ј-untranslated region of Tf receptor mRNA (13-17). In irondepleted cells, IRPs bind with high affinity to the IREs, resulting in suppression of ferritin mRNA translation and stabilization of Tf receptor mRNA (incr...

show abstract

Succinate Dehydrogenase b mRNA of Drosophila melanogaster Has a Functional Iron-responsive Element in Its 5′-Untranslated Region

Cited by 126 publications

References 36 publications

Regulation of iron metabolism in the sanguivore lamprey Lampetra fluviatilis

Regulation of iron metabolism in the sanguivore lamprey Lampetra fluviatilis

Ribosomal Pausing and Scanning Arrest as Mechanisms of Translational Regulation from Cap-Distal Iron-Responsive Elements

Resistance to the Antitumor Agent Gallium Nitrate in Human Leukemic Cells Is Associated with Decreased Gallium/Iron Uptake, Increased Activity of Iron Regulatory Protein-1, and Decreased Ferritin Production

Contact Info

Product

Resources

About