Journal of Microbiology

Soo-Yeon Cho

1 Article

Non-mitochondrial aconitase regulates the expression of iron-uptake genes by controlling the RNA turnover process in fission yeast: Soo-Yeon Cho , Soo-Jin Jung , Kyoung-Dong Kim , Jung-Hye Roe; J. Microbiol. 2021;59(12):1075-1082. Published online October 26, 2021; DOI: https://doi.org/10.1007/s12275-021-1438-4

75 View
0 Download
5 Web of Science
5 Crossref

Aconitase, a highly conserved protein across all domains of life, functions in converting citrate to isocitrate in the tricarboxylic acid cycle. Cytosolic aconitase is also known to act as an iron regulatory protein in mammals, binding to the RNA hairpin structures known as iron-responsive elements within the untranslated regions of specific RNAs. Aconitase-2 (Aco2) in fission yeast is a fusion protein consisting of an aconitase and a mitochondrial ribosomal protein, bL21, residing not only in mitochondria but also in cytosol and the nucleus. To investigate the role of Aco2 in the nucleus and cytoplasm of fission yeast, we analyzed the transcriptome of aco2ΔN mutant that is deleted of nuclear localization signal (NLS). RNA sequencing revealed that the aco2ΔN mutation caused increase in mRNAs encoding iron uptake transporters, such as Str1, Str3, and Shu1. The half-lives of mRNAs for these genes were found to be significantly longer in the aco2ΔN mutant than the wild-type strain, suggesting the role of Aco2 in mRNA turnover. The three conserved cysteines required for the catalytic activity of aconitase were not necessary for this role. The UV cross-linking RNA immunoprecipitation analysis revealed that Aco2 directly bound to the mRNAs of iron uptake transporters. Aco2-mediated degradation of iron-uptake mRNAs appears to utilize exoribonuclease pathway that involves Rrp6 as evidenced by genetic interactions. These results reveal a novel role of non-mitochondrial aconitase protein in the mRNA turnover in fission yeast to fine-tune iron homeostasis, independent of regulation by transcriptional repressor Fep1.

Citations

Citations to this article as recorded by

Iron-mediated post-transcriptional regulation in Toxoplasma gondii
Megan A. Sloan, Adam Scott, Dana Aghabi, Lucia Mrvova, Clare R. Harding, Dominique Soldati-Favre
PLOS Pathogens.2025; 21(2): e1012857. CrossRef
The Key Enzymes of Carbon Metabolism and the Glutathione Antioxidant System Protect Yarrowia lipolytica Yeast Against pH-Induced Stress
Tatyana I. Rakhmanova, Natalia N. Gessler, Elena P. Isakova, Olga I. Klein, Yulia I. Deryabina, Tatyana N. Popova
Journal of Fungi.2024; 10(11): 747. CrossRef
The intricate link between iron, mitochondria and azoles in Candida species
Wouter Van Genechten, Rudy Vergauwen, Patrick Van Dijck
The FEBS Journal.2024; 291(16): 3568. CrossRef
Non-Mitochondrial Aconitase-2 Mediates the Transcription of Nuclear-Encoded Electron Transport Chain Genes in Fission Yeast
Ho-Jung Kim, Soo-Yeon Cho, Soo-Jin Jung, Yong-Jun Cho, Jung-Hye Roe, Kyoung-Dong Kim
Journal of Microbiology.2024; 62(8): 639. CrossRef
Kinetic and Regulatory Properties of Yarrowia lipolytica Aconitate Hydratase as a Model-Indicator of Cell Redox State under pH Stress
Tatyana I. Rakhmanova, Varvara Yu. Sekova, Natalya N. Gessler, Elena P. Isakova, Yulia I. Deryabina, Tatyana N. Popova, Yevgeniya I. Shurubor, Boris F. Krasnikov
International Journal of Molecular Sciences.2023; 24(8): 7670. CrossRef

Soo-Yeon Cho

1 Article

Non-Mitochondrial Aconitase-2 Mediates the Transcription of Nuclear-Encoded Electron Transport Chain Genes in Fission Yeast: Ho-Jung Kim, Soo-Yeon Cho, Soo-Jin Jung, Yong-Jun Cho, Jung-Hye Roe, Kyoung-Dong Kim; J. Microbiol. 2024;62(8):639-648. Published online June 25, 2024; DOI: https://doi.org/10.1007/s12275-024-00147-8

80 View
0 Download

Abstract: Aconitase-2 (Aco2) is present in the mitochondria, cytosol, and nucleus of fission yeast. To explore its function beyond the well-known role in the mitochondrial tricarboxylic acid (TCA) cycle, we conducted genome-wide profiling using the aco2ΔNLS mutant, which lacks a nuclear localization signal (NLS). The RNA sequencing (RNA-seq) data showed a general downregulation of electron transport chain (ETC) genes in the aco2ΔNLS mutant, except for those in the complex II, leading to a growth defect in respiratory-prone media. Complementation analysis with non-catalytic Aco2 [aco2ΔNLS + aco2(3CS)], where three cysteines were substituted with serine, restored normal growth and typical ETC gene expression. This suggests that Aco2's catalytic activity is not essential for its role in ETC gene regulation. Our mRNA decay assay indicated that the decrease in ETC gene expression was due to transcriptional regulation rather than changes in mRNA stability. Additionally, we investigated the Php complex's role in ETC gene regulation and found that ETC genes, except those within complex II, were downregulated in php3Δ and php5Δ strains, similar to the aco2ΔNLS mutant. These findings highlight a novel role for nuclear aconitase in ETC gene regulation and suggest a potential connection between the Php complex and Aco2.

Author index