A Novel “Oxygen-induced” Greening Process in a Cyanobacterial Mutant Lacking the Transcriptional Activator ChlR Involved in Low-oxygen Adaptation of Tetrapyrrole Biosynthesis

Aoki, Rina; Hiraide, Yuto; Yamakawa, Hisanori; Fujita, Yuichi

doi:10.1074/jbc.m113.495358

Cited by 15 publications

(12 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Also, it was observed that expression of psbA1 , which encodes the low-oxygen induced D1′ protein, is activated by ChlR [150] . The lack of psbA1 on the other hand did not affect D1 levels, whereas D1 levels were decreased under low-oxygen conditions in mutants lacking either ChlR or the low-oxygen induced tetrapyrrole biosynthesis genes, indicating that the decrease of D1 under these latter conditions is caused by chlorophyll deficiency [150,151] . Other reports in planta implicated tetrapyrrole chromophore biosynthesis as positively correlated with holophytochrome synthesis [152] .…”

Section: Function Of Tetrapyrroles As Signaling Molecules and The Oximentioning

confidence: 85%

“…Recently it has been observed that Synechocystis cells lacking ChlR, which is a positive regulator of oxygen-independent tetrapyrrole biosynthesis enzymes, are unable to induce the greening process in the light under low-oxygen conditions [150] . When the greening process is induced in the mutant under oxygen-sufficient conditions which allow oxygen-dependent tetrapyrrole biosynthesis needed for chlorophyll biosynthesis, the chlorophyll content increased concurrently with the other photosystem components [151] . These findings indicate that the levels of tetrapyrroles influence accumulation of the respective tetrapyrrole-requiring protein components to ensure that the complex components are only synthesized if a fully functional complex can be assembled.…”

Section: Function Of Tetrapyrroles As Signaling Molecules and The Oximentioning

confidence: 99%

See 1 more Smart Citation

Interdependence of tetrapyrrole metabolism, the generation of oxidative stress and the mitigative oxidative stress response

Busch

Montgomery

2015

Redox Biology

View full text Add to dashboard Cite

Tetrapyrroles are involved in light harvesting and light perception, electron-transfer reactions, and as co-factors for key enzymes and sensory proteins. Under conditions in which cells exhibit stress-induced imbalances of photosynthetic reactions, or light absorption exceeds the ability of the cell to use photoexcitation energy in synthesis reactions, redox imbalance can occur in photosynthetic cells. Such conditions can lead to the generation of reactive oxygen species (ROS) associated with alterations in tetrapyrrole homeostasis. ROS accumulation can result in cellular damage and detrimental effects on organismal fitness, or ROS molecules can serve as signals to induce a protective or damage-mitigating oxidative stress signaling response in cells. Induced oxidative stress responses include tetrapyrrole-dependent and -independent mechanisms for mitigating ROS generation and/or accumulation. Thus, tetrapyrroles can be contributors to oxidative stress, but are also essential in the oxidative stress response to protect cells by contributing to detoxification of ROS. In this review, we highlight the interconnection and interdependence of tetrapyrrole metabolism with the occurrence of oxidative stress and protective oxidative stress signaling responses in photosynthetic organisms.

show abstract

Section: Function Of Tetrapyrroles As Signaling Molecules and The Oximentioning

confidence: 85%

Section: Function Of Tetrapyrroles As Signaling Molecules and The Oximentioning

confidence: 99%

Interdependence of tetrapyrrole metabolism, the generation of oxidative stress and the mitigative oxidative stress response

Busch

Montgomery

2015

Redox Biology

View full text Add to dashboard Cite

show abstract

“…The transcript levels of 23 genes for Chl biosynthesis ( gltX , hemA , hemL , hemB , hemC , hemD , hemE , hemF , hemN , hemJ , chlD , chlH , chlI , gun4 , chlM , chlA I , chlA II , cvrA , por , chlL , chlN , chlB and chlG ) and five genes for photosystems ( psaA , psaB , psaC , psbA2/A3 and psbO ) were examined by semi-quantitative reverse-transcriptase PCR in wild-type and ∆chlR cells grown under aerobic and microoxic conditions. Except for chlA II and hemN , the transcript levels of the other 26 genes were almost the same in wild-type and ∆chlR , irrespective of aerobic and microoxic conditions [ 108 ]. Thus, chlA II , ho2 , hemN and psbA1 may only be the ChlR-targets in Synechocystis 6803.…”

Section: Transcriptional Regulator Chlrmentioning

confidence: 99%

Evolutionary Aspects and Regulation of Tetrapyrrole Biosynthesis in Cyanobacteria under Aerobic and Anaerobic Environments

Fujita

Tsujimoto

Aoki

2015

Life

Self Cite

View full text Add to dashboard Cite

Chlorophyll a (Chl) is a light-absorbing tetrapyrrole pigment that is essential for photosynthesis. The molecule is produced from glutamate via a complex biosynthetic pathway comprised of at least 15 enzymatic steps. The first half of the Chl pathway is shared with heme biosynthesis, and the latter half, called the Mg-branch, is specific to Mg-containing Chl a. Bilin pigments, such as phycocyanobilin, are additionally produced from heme, so these light-harvesting pigments also share many common biosynthetic steps with Chl biosynthesis. Some of these common steps in the biosynthetic pathways of heme, Chl and bilins require molecular oxygen for catalysis, such as oxygen-dependent coproporphyrinogen III oxidase. Cyanobacteria thrive in diverse environments in terms of oxygen levels. To cope with Chl deficiency caused by low-oxygen conditions, cyanobacteria have developed elaborate mechanisms to maintain Chl production, even under microoxic environments. The use of enzymes specialized for low-oxygen conditions, such as oxygen-independent coproporphyrinogen III oxidase, constitutes part of a mechanism adapted to low-oxygen conditions. Another mechanism adaptive to hypoxic conditions is mediated by the transcriptional regulator ChlR that senses low oxygen and subsequently activates the transcription of genes encoding enzymes that work under low-oxygen tension. In diazotrophic cyanobacteria, this multilayered regulation also contributes in Chl biosynthesis by supporting energy production for nitrogen fixation that also requires low-oxygen conditions. We will also discuss the evolutionary implications of cyanobacterial tetrapyrrole biosynthesis and regulation, because low oxygen-type enzymes also appear to be evolutionarily older than oxygen-dependent enzymes.

show abstract

“…Protein concentration was determined by Bradford assay (Protein Assay, Bio-Rad, Hercules, CA) with bovine serum albumin as the standard. Western blot analysis was carried out as described previously 55 . The specific protein bands were visualized by a lumino-image analyzer (LAS-3000mini, Fujifilm, Tokyo, Japan).…”

Section: Methodsmentioning

confidence: 99%

Functional expression of an oxygen-labile nitrogenase in an oxygenic photosynthetic organism

Tsujimoto

Kotani

Yokomizo

et al. 2018

Sci Rep

Self Cite

View full text Add to dashboard Cite

Transfer of nitrogen fixation ability to plants, especially crops, is a promising approach to mitigate dependence on chemical nitrogen fertilizer and alleviate environmental pollution caused by nitrogen fertilizer run-off. However, the need to transfer a large number of nitrogen fixation (nif) genes and the extreme vulnerability of nitrogenase to oxygen constitute major obstacles for transfer of nitrogen-fixing ability to plants. Here we demonstrate functional expression of a cyanobacterial nitrogenase in the non-diazotrophic cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis 6803). A 20.8-kb chromosomal fragment containing 25 nif and nif-related genes of the diazotrophic cyanobacterium Leptolyngbya boryana was integrated into a neutral genome site of Synechocystis 6803 by five-step homologous recombination together with the cnfR gene encoding the transcriptional activator of the nif genes to isolate CN1. In addition, two other transformants CN2 and CN3 carrying additional one and four genes, respectively, were isolated from CN1. Low but significant nitrogenase activity was detected in all transformants. This is the first example of nitrogenase activity detected in non-diazotrophic photosynthetic organisms. These strains provide valuable platforms to investigate unknown factors that enable nitrogen-fixing growth of non-diazotrophic photosynthetic organisms, including plants.

show abstract

A Novel “Oxygen-induced” Greening Process in a Cyanobacterial Mutant Lacking the Transcriptional Activator ChlR Involved in Low-oxygen Adaptation of Tetrapyrrole Biosynthesis

Cited by 15 publications

References 35 publications

Interdependence of tetrapyrrole metabolism, the generation of oxidative stress and the mitigative oxidative stress response

Interdependence of tetrapyrrole metabolism, the generation of oxidative stress and the mitigative oxidative stress response

Evolutionary Aspects and Regulation of Tetrapyrrole Biosynthesis in Cyanobacteria under Aerobic and Anaerobic Environments

Functional expression of an oxygen-labile nitrogenase in an oxygenic photosynthetic organism

Contact Info

Product

Resources

About