Restricted expression of NADPH oxidase/peroxidase gene (Duox) in zone VII of the ascidian endostyle

Hiruta, Jin; Mazet, Françoise; Ogasawara, Michio

doi:10.1007/s00441-006-0220-6

Cited by 16 publications

(5 citation statements)

References 22 publications

(25 reference statements)

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“…Duox1 and Duox2 are expressed in thyroid [92], and an ascidian ortholog of Duox is expressed in the endostyle, which is regarded as the primitive homolog of the thyroid gland in vertebrates [123]. Human Duox1 is also highly expressed in the lung, pancreas, placenta, prostate, testis, and salivary gland [90].…”

Section: F Regulation Of Duox Expressionmentioning

confidence: 99%

Regulation of Nox and Duox enzymatic activity and expression

Lambeth

Kawahara

Diebold

2007

Free Radical Biology and Medicine

453

422

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SummaryIn recent years, it has become clear that reactive oxygen species (ROS, which include superoxide, hydrogen peroxide and other metabolites) are produced in biological systems. Rather than being simply a byproduct of aerobic metabolism, it is now recognized that specific enzymes ---the Nox (NADPH-oxidase) and Duox (Dual oxidase) enzymes ----seem to have the sole function of generating ROS in a carefully regulated manner, and key roles in signal transduction, immune function, hormone biosynthesis and other normal biological functions are being uncovered. The prototypical Nox is the respiratory burst oxidase or phagocyte oxidase, which generates large amounts of superoxide and other reactive species in the phagosomes of neutrophils and macrophages, playing a central role in innate immunity by killing microbes. This enzyme system has been extensively studied over the past two decades, and provides a basis for comparison with the more recently described Nox and Duox enzymes, which generate ROS in a variety of cells and tissues. This review first considers the structure and regulation of the respiratory burst oxidase, and then reviews recent studies relating to the regulation of the activity of the novel Nox/Duox enzymes. The regulation of Nox and Duox expression in tissues and by specific stimuli is also considered here. An accompanying review considers biological and pathological roles of the Nox family of enzymes. The Respiratory Burst Oxidase of Phagocytes a. The respiratory burstThe "respiratory burst" refers to the early observation that when professional phagocytes such as neutrophils and macrophages are exposed to microbes, they consume large amounts of oxygen. Unexpectedly, this oxygen consumption was not inhibited by cyanide, an inhibitor of mitochondrial electron transport. This observation led to a more than 25 year search for the enzymatic origin of the respiratory burst and to the eventual discovery and molecular characterization of the phagocytic NADPH-oxidase or "respiratory burst oxidase". The phagocyte oxidase generates superoxide via the one electron-reduction of oxygen by NADPH, with secondary production of hydrogen peroxide, HOCl and other activated forms of oxygen. Together, these reactive oxygen species (ROS) participate in host defense by killing invading microbes. b. gp91 phox , the catalytic moiety of the respiratory burst oxidaseThe phagocytic NADPH-oxidase consists of a membrane-localized glycosylated, catalytic subunit, gp91 phox (which has also come to be known as Nox2, a terminology that will be used in this review), along with a second membrane-associated subunit, p22 phox , both depicted in Fig. 1. Nox2 and p22 phox stabilize one another in a tightly associated heterodimer which is referred to as flavocytochrome b 558 . The C-terminal half of Nox2 forms a domain that is Contact information: 148 Whitehead Biomedical Research Building, Department of Pathology and Laboratory Medicine, 615 Michael Street, Atlanta, GA 30322, U.S. A. Phone: 404-727-5875, Fax: 404-712-2979, e-mail: nox...

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Section: F Regulation Of Duox Expressionmentioning

confidence: 99%

Regulation of Nox and Duox enzymatic activity and expression

Lambeth

Kawahara

Diebold

2007

Free Radical Biology and Medicine

453

422

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“…Nox4 was expressed in blood cells and in the endostyle, a ciliated, mucous-secreting groove that aids in transporting food to the esophagus. The endostyle has iodine-concentrating and peroxidase activities, is capable of iodination reactions, and is considered to be homologous to the follicular thyroid of higher organisms [74]. This raises the interesting possibility that Nox4 functions in a manner analogous to Duox in mammalian thyroid, providing H 2 O 2 substrate for secreted peroxidases that catalyze iodination reactions.…”

Section: Urochordatesmentioning

confidence: 99%

Nox enzymes from fungus to fly to fish and what they tell us about Nox function in mammals

Aguirre¹,

Lambeth²

2010

Free Radical Biology and Medicine

137

117

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The production of reactive oxygen species (ROS) in a highly regulated fashion is a hallmark of members of the NADPH oxidase (Nox) family of enzymes. Nox enzymes are present in most eukaryotic groups such as the amebozoid, fungi, algae and plants, and animals, where they are involved in seemingly diverse biological processes. However, a comprehensive survey of Nox functions throughout biology reveals common functional themes. Noxes are often activated in response to stressful conditions such as nutrient starvation, physical damage or pathogen attack. Although the end result varies depending on the organism and tissue, Nox-produced ROS mediates the response to the adverse stimuli, such as innate immunity responses in plant and animals or cell differentiation in Dictyostelium, fungi and plants. These responses involve ROS-mediated signaling mechanisms occurring at intracellular or cell-to-cell levels, and sometimes involve cell wall or extracellular matrix cross-linking. Indeed, Noxes are involved in local and systemic signaling from plants to fish, and in cross-linking of the plant hair-cell wall, synthesis of the nematode cuticle and formation the sea urchin fertilization envelope. The extensive use of Nox enzymes in biology to regulate cell-to-cell signaling and morphogenesis suggest that additional functions in mammalian signaling and development remain to be discovered.

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“…Piwi staining in the endostyle of recently settled and metamorphosing larvae appears to be mostly nuclear, whereas expression in zone 4 of the endostyle in older colonies extends to the cytoplasm as well. The ascidian endostyle is involved in secretion of mucus and digestive enzymes and certain regions also bind and metabolize iodine (Burighel and Cloney, '97;Hiruta et al, 2006). Zones 2, 4 and 6 are specialized for secretion; while little is known about differences among these zones, there are a few examples of differing gene expression and ultrastructure (Pestarino,'92;Burighel and Cloney,'97;Ogasawara and Satoh,'98).…”

Section: Piwi-positive Cells In B Violaceusmentioning

confidence: 99%

Whole body regeneration in a colonial ascidian, Botrylloides violaceus

Brown

Keeling

et al. 2009

J Exp Zool Pt B

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Colonial ascidians are the only chordates to undergo whole body regeneration (WBR), the ability to form an entirely new individual from the peripheral vasculature. Here we describe WBR in Botrylloides violaceus, a colonial ascidian that reliably regenerates after ablation of all zooids and buds of young colonies. During early regeneration several buds develop within the tunic vasculature, but only one continues development into a complete zooid. We describe some of the first events of vascular budding leading to the vesicle stage with phase contrast microscopy, time-lapse video recording and detailed histological studies of regenerating colonies. The first conspicuous stage of vascular budding is when a single-layered sphere of cells becomes enclosed by vascular epithelium. We report the appearance of Piwi-positive cells in hemocytes surrounding the regenerates. We observed an increase of proliferating cell nuclear antigen (PCNA)-positive cells in circulatory hemocytes in late regenerates, and found double-labeled nuclear expression with Piwi in a subset of large circulatory cells. We rarely found Piwi or PCNA in differentiating tissues during vascular budding, suggesting that cells that form the epithelial tissues during budding and WBR originate mostly from circulatory hemocyte precursors. We propose that multiple stem cell types are circulating within B. violaceus and that they undergo proliferation in the peripheral vasculature before differentiating into epithelial tissues for all three germ layers during WBR.

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Restricted expression of NADPH oxidase/peroxidase gene (Duox) in zone VII of the ascidian endostyle

Cited by 16 publications

References 22 publications

Regulation of Nox and Duox enzymatic activity and expression

Regulation of Nox and Duox enzymatic activity and expression

Nox enzymes from fungus to fly to fish and what they tell us about Nox function in mammals

Whole body regeneration in a colonial ascidian, Botrylloides violaceus

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