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Truncated Hemoglobins 1 and 2 Are Implicated in the Modulation of Phosphorus Deficiency-Induced Nitric Oxide Levels in Chlamydomonas

Truncated hemoglobins (trHbs) form a widely distributed family of proteins found in archaea, bacteria, and eukaryotes. Accumulating evidence suggests that trHbs may be implicated in functions other than oxygen delivery, but these roles are largely unknown. Characterization of the conditions that aff...

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Autores principales: Filina, Valentina, Grinko, Alexandra, Ermilova, Elena
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6770159/
https://www.ncbi.nlm.nih.gov/pubmed/31438612
http://dx.doi.org/10.3390/cells8090947
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author Filina, Valentina
Grinko, Alexandra
Ermilova, Elena
author_facet Filina, Valentina
Grinko, Alexandra
Ermilova, Elena
author_sort Filina, Valentina
collection PubMed
description Truncated hemoglobins (trHbs) form a widely distributed family of proteins found in archaea, bacteria, and eukaryotes. Accumulating evidence suggests that trHbs may be implicated in functions other than oxygen delivery, but these roles are largely unknown. Characterization of the conditions that affect trHb expression and investigation of their regulatory mechanisms will provide a framework for elucidating the functions of these globins. Here, the transcription of Chlamydomonas trHb genes (THB1–12) under conditions of phosphorus (P) deprivation was analyzed. Three THB genes, THB1, THB2, and THB12 were expressed at the highest level. For the first time, we demonstrate the synthesis of nitric oxide (NO) under P-limiting conditions and the production of NO by cells via a nitrate reductase-independent pathway. To clarify the functions of THB1 and THB2, we generated and analyzed strains in which these THBs were strongly under-expressed by using an artificial microRNA approach. Similar to THB1 knockdown, the depletion of THB2 led to a decrease in cell size and chlorophyll levels. We provide evidence that the knockdown of THB1 or THB2 enhanced NO production under P deprivation. Overall, these results demonstrate that THB1 and THB2 are likely to contribute, at least in part, to acclimation responses in P-deprived Chlamydomonas.
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spelling pubmed-67701592019-10-30 Truncated Hemoglobins 1 and 2 Are Implicated in the Modulation of Phosphorus Deficiency-Induced Nitric Oxide Levels in Chlamydomonas Filina, Valentina Grinko, Alexandra Ermilova, Elena Cells Article Truncated hemoglobins (trHbs) form a widely distributed family of proteins found in archaea, bacteria, and eukaryotes. Accumulating evidence suggests that trHbs may be implicated in functions other than oxygen delivery, but these roles are largely unknown. Characterization of the conditions that affect trHb expression and investigation of their regulatory mechanisms will provide a framework for elucidating the functions of these globins. Here, the transcription of Chlamydomonas trHb genes (THB1–12) under conditions of phosphorus (P) deprivation was analyzed. Three THB genes, THB1, THB2, and THB12 were expressed at the highest level. For the first time, we demonstrate the synthesis of nitric oxide (NO) under P-limiting conditions and the production of NO by cells via a nitrate reductase-independent pathway. To clarify the functions of THB1 and THB2, we generated and analyzed strains in which these THBs were strongly under-expressed by using an artificial microRNA approach. Similar to THB1 knockdown, the depletion of THB2 led to a decrease in cell size and chlorophyll levels. We provide evidence that the knockdown of THB1 or THB2 enhanced NO production under P deprivation. Overall, these results demonstrate that THB1 and THB2 are likely to contribute, at least in part, to acclimation responses in P-deprived Chlamydomonas. MDPI 2019-08-21 /pmc/articles/PMC6770159/ /pubmed/31438612 http://dx.doi.org/10.3390/cells8090947 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Filina, Valentina
Grinko, Alexandra
Ermilova, Elena
Truncated Hemoglobins 1 and 2 Are Implicated in the Modulation of Phosphorus Deficiency-Induced Nitric Oxide Levels in Chlamydomonas
title Truncated Hemoglobins 1 and 2 Are Implicated in the Modulation of Phosphorus Deficiency-Induced Nitric Oxide Levels in Chlamydomonas
title_full Truncated Hemoglobins 1 and 2 Are Implicated in the Modulation of Phosphorus Deficiency-Induced Nitric Oxide Levels in Chlamydomonas
title_fullStr Truncated Hemoglobins 1 and 2 Are Implicated in the Modulation of Phosphorus Deficiency-Induced Nitric Oxide Levels in Chlamydomonas
title_full_unstemmed Truncated Hemoglobins 1 and 2 Are Implicated in the Modulation of Phosphorus Deficiency-Induced Nitric Oxide Levels in Chlamydomonas
title_short Truncated Hemoglobins 1 and 2 Are Implicated in the Modulation of Phosphorus Deficiency-Induced Nitric Oxide Levels in Chlamydomonas
title_sort truncated hemoglobins 1 and 2 are implicated in the modulation of phosphorus deficiency-induced nitric oxide levels in chlamydomonas
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6770159/
https://www.ncbi.nlm.nih.gov/pubmed/31438612
http://dx.doi.org/10.3390/cells8090947
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