Translational control of catalase synthesis by hemin in the yeast
            <i>Saccharomyces cerevisiae</i>

Hamilton, Barbara; Hofbauer, Roland; Ruis, Helmut

doi:10.1073/pnas.79.24.7609

Cited by 22 publications

(4 citation statements)

References 34 publications

(27 reference statements)

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“…Usually the decrease in activity of an enzyme under such conditions may be due either to decrease of enzyme synthesis, or increase of enzyme degradation, or alternatively to conformational changes and reduced structural stability of the enzyme molecule. Although there is evidence in the literature for a decrease in protein synthesis due to salinity (Cooke et al 1973, Hall and Flowers 1973, Hamilton et al 1982, Kahane and Poljakoff-Mayber 1968, this does not seem to explain the decrease in activity in the present case. Thus, total protein increased in the tissue due to exposure to salinity and the partitioning of protein and of enzyme activity between the different (N1H4)2SO4 fractions was very similar.…”

Section: Discussioncontrasting

confidence: 84%

Peroxidase and catalase activity in leaves of Halimione portulacoides exposed to salinity

Kalir

Omri

Poljakoff‐Mayber

1984

Physiologia Plantarum

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1984. Peroxidase and catalase activity in leaves of Halimione portuiacoides exposed to salinity. -Physiol. Plant. 62; 238-244.The effect of high NaCl concentrations on the activity of catalase (EC 1.11.1.6), peroxidase (EC 1.11.1.7) and malate dehydrogenase (NAD+-linked; EC 1.1.1.37) from leaves of Halimione portuiacoides (L.) Aelien was studied. The plants were exposed to high salinity during growth and enzyme activity was measured either in the absence or in the presence of various concentrations of NaCl. Increasing salinity in vitro induced three types of effects; (1) an increase in activity (peroxidase); (2) a decrease in activity (catalase); (3) stimulation by low salt concentration but inhibition by higher concentrations (malate dehydrogenase). Salinity in vivo induced a marked decrease in catalase and maiate dehydrogenase activities. However, peroxidase in vivo showed an optimum curve of activity vs external NaCl concentration, with an optimum at ca 1 JW NaCI. Exposure of plants to salinity induced changes in the properties of the enzyme proteins; they precipitated at a higher (NH4)2SO4 concentration, were eluted later during Sephadex G-200 filtration, and showed a shift in the maximal, minimal and optimal temperatures. These data are interpreted as evidence for conformational changes in the enzymes due to prolonged exposure to high salinity stress; such changes could be disruption into monomers (catalase and malate dehydrogenase), or changes in molecular shape (in the peroxidase).Additional key words -Malate dehydrogenase.

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Section: Discussioncontrasting

confidence: 84%

Peroxidase and catalase activity in leaves of Halimione portulacoides exposed to salinity

Kalir

Omri

Poljakoff‐Mayber

1984

Physiologia Plantarum

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“…However, the situation in yeast is less clear. Evidence has been presented that is consistent with translational regulation of the mRNAs encoding catalase (197) and the ribosomal protein L32 (109) in S. cerevisiae. However, in neither case has the regulatory mechanism been defined, and the results reported were not indicative of the operation of a high degree of control.…”

Section: Gene-specific Regulation Via Trans-acting Factorsmentioning

confidence: 58%

Posttranscriptional Control of Gene Expression in Yeast

McCarthy

1998

Microbiol Mol Biol Rev

212

133

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SUMMARY Studies of the budding yeast Saccharomyces cerevisiae have greatly advanced our understanding of the posttranscriptional steps of eukaryotic gene expression. Given the wide range of experimental tools applicable to S. cerevisiae and the recent determination of its complete genomic sequence, many of the key challenges of the posttranscriptional control field can be tackled particularly effectively by using this organism. This article reviews the current knowledge of the cellular components and mechanisms related to translation and mRNA decay, with the emphasis on the molecular basis for rate control and gene regulation. Recent progress in characterizing translation factors and their protein-protein and RNA-protein interactions has been rapid. Against the background of a growing body of structural information, the review discusses the thermodynamic and kinetic principles that govern the translation process. As in prokaryotic systems, translational initiation is a key point of control. Modulation of the activities of translational initiation factors imposes global regulation in the cell, while structural features of particular 5′ untranslated regions, such as upstream open reading frames and effector binding sites, allow for gene-specific regulation. Recent data have revealed many new details of the molecular mechanisms involved while providing insight into the functional overlaps and molecular networking that are apparently a key feature of evolving cellular systems. An overall picture of the mechanisms governing mRNA decay has only very recently begun to develop. The latest work has revealed new information about the mRNA decay pathways, the components of the mRNA degradation machinery, and the way in which these might relate to the translation apparatus. Overall, major challenges still to be addressed include the task of relating principles of posttranscriptional control to cellular compartmentalization and polysome structure and the role of molecular channelling in these highly complex expression systems.

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“…Hemin is known to exert regulatory effects on both transcription and translation of catalases and other hemoprotein genes, such as cytochromes, in yeast (reviewed by Ruis and Koller, 1997). A stimulation of translation by hemin was observed for catalase A and T mRNAs of Saccharomyces cerevisiae (Hamilton et al ., 1982). In irradiated rye leaves, the availability of hemin can represent a suitable indicator of light intensity because both the synthesis of new hemin and the liberation of hemin from photoinactivated catalase increase with the photon flux, and the hemin cofactor is not photodegraded during the turnover of catalase (Feierabend and Dehne, 1996).…”

Section: Discussionmentioning

confidence: 99%

Post‐transcriptional mechanisms control catalase synthesis during its light‐induced turnover in rye leaves through the availability of the hemin cofactor and reversible changes of the translation efficiency of mRNA

Schmidt

Dehne

Feierabend³

2002

The Plant Journal

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SummaryThe enzyme catalase is light-sensitive. In leaves, losses caused by photoinactivation are replaced by new enzyme and the rate of de novo synthesis must be rapidly and¯exibly attuned to¯uctuating light conditions. In mature rye leaves, post-transcriptional mechanisms were shown to control the rate of catalase synthesis. The amount of the leaf catalase (CAT-1) transcript did not increase with light intensity, but was even higher after dark exposure of light-grown leaves. Initiation was apparently not limiting translation in the dark, as the association of the Cat1 mRNA with polysomes did not change notably under different light conditions. By analysing the translation of catalase polypeptides in cell-free systems with poly(A)+ RNA from leaves or with mRNA transcribed from a Cat1-containing cDNA clone, two mechanisms of post-transcriptional control were identi®ed. First, translation of catalase depended on the presence of hemin. In leaves, the availability of hemin may signal the extent of catalase degradation as the hemin of the inactivated enzyme is recycled. Second, the translation ef®ciency of the Cat1 transcripts was reversibly modulated in a dose-dependent manner by the light intensity to which leaves were exposed, prior to extraction. The Cat1 mRNA from light-exposed leaves was translated much more ef®ciently than mRNA from dark-exposed leaves. The increase of its translation activity in vivo was not blocked by cordycepin but was suppressed by methylation inhibitors, indicating a reversible modi®cation of pre-existing mRNA by methylation. Translation of in vitro synthesized Cat1 mRNA required a methylated cap (m7GpppG), but was virtually below detection when it contained an unmethylated cap (GpppG).

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Translational control of catalase synthesis by hemin in the yeast Saccharomyces cerevisiae

Cited by 22 publications

References 34 publications

Peroxidase and catalase activity in leaves of Halimione portulacoides exposed to salinity

Peroxidase and catalase activity in leaves of Halimione portulacoides exposed to salinity

Posttranscriptional Control of Gene Expression in Yeast

Post‐transcriptional mechanisms control catalase synthesis during its light‐induced turnover in rye leaves through the availability of the hemin cofactor and reversible changes of the translation efficiency of mRNA

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