Characterization of cDNAs encoding putative laccase-like multicopper oxidases and developmental expression in the tobacco hornworm, Manduca sexta, and the malaria mosquito, Anopheles gambiae

Dittmer, Neal T.; Suderman, Richard J.; Jiang, Haobo; Zhu, Yu‐Cheng; Gorman, Maureen J.; Kramer, Karl J.; Kanost, Michael R.

doi:10.1016/j.ibmb.2003.08.003

Cited by 178 publications

(169 citation statements)

References 73 publications

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“…Previous studies of gene expression in D. melanogaster found that MCO1 mRNA is most abundant in late stage embryos, feeding stage larvae, and adults, and that MCO1 is expressed predominantly in the digestive system (midgut, hindgut, and crop) and Malpighian tubules (17,18). These expression profiles are similar to those of MCO1 orthologues in Anopheles gambiae and Manduca sexta (19)(20)(21). To establish whether MCO1 functions as a ferroxidase in D. melanogaster, we purified recombinant MCO1 and analyzed its enzymatic activity, performed immunohistochemistry to determine the location of MCO1 within the insect, and evaluated the loss-of-function phenotypes generated by RNAi-mediated knockdown.…”

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confidence: 56%

Multicopper oxidase-1 is a ferroxidase essential for iron homeostasis in Drosophila melanogaster

Lang

Braun

Kanost

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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Multicopper ferroxidases catalyze the oxidation of ferrous iron to ferric iron. In yeast and algae, they participate in cellular uptake of iron; in mammals, they facilitate cellular efflux. The mechanisms of iron metabolism in insects are still poorly understood, and insect multicopper ferroxidases have not been identified. In this paper, we present evidence that Drosophila melanogaster multicopper oxidase-1 (MCO1) is a functional ferroxidase. We identified candidate iron-binding residues in the MCO1 sequence and found that purified recombinant MCO1 oxidizes ferrous iron. An association between MCO1 function and iron homeostasis was confirmed by two observations: RNAi-mediated knockdown of MCO1 resulted in decreased iron accumulation in midguts and whole insects, and weak knockdown increased the longevity of flies fed a toxic concentration of iron. Strong knockdown of MCO1 resulted in pupal lethality, indicating that MCO1 is an essential gene. Immunohistochemistry experiments demonstrated that MCO1 is located on the basal surfaces of the digestive system and Malpighian tubules. We propose that MCO1 oxidizes ferrous iron in the hemolymph and that the resulting ferric iron is bound by transferrin or melanotransferrin, leading to iron storage, iron withholding from pathogens, regulation of oxidative stress, and/or epithelial maturation. These proposed functions are distinct from those of other known ferroxidases. Given that MCO1 orthologues are present in all insect genomes analyzed to date, this discovery is an important step toward understanding iron metabolism in insects.

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confidence: 56%

Multicopper oxidase-1 is a ferroxidase essential for iron homeostasis in Drosophila melanogaster

Lang

Braun

Kanost

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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“…Whereas tyrosinases, which are oxidases that contain two copper ions and catalyze the oxidation of ortho-diphenols, have been studied extensively for their roles in melanization, wound healing, and insect immunity (7,(9)(10)(11), less information is available about the importance in insect developmental physiology of laccases, which are oxidases that contain four copper ions and have ortho-and para-diphenol oxidizing activities (4,12). To establish the involvement of either or both of these phenoloxidase genes in insect cuticle tanning, RNA interference (RNAi) experiments were performed by using the red flour beetle Tribolium castaneum, an economically important agricultural pest species that is exquisitely sensitive to dsRNAmediated posttranscriptional gene silencing (13,14).…”

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confidence: 99%

Laccase 2 is the phenoloxidase gene required for beetle cuticle tanning

Arakane

Muthukrishnan

Beeman

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

353

343

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Cuticle tanning (or sclerotization and pigmentation) in invertebrates involves the oxidative conjugation of proteins, which renders them insoluble and hardens and darkens the color of the exoskeleton. Two kinds of phenoloxidases, laccase and tyrosinase, have been proposed to participate in tanning, but proof of the true identity of the enzyme(s) responsible for this process has been elusive. We report the cloning of cDNAs for laccases and tyrosinases from the red flour beetle, Tribolium castaneum, as well as their developmental patterns of expression. To test for the involvement of these types of enzymes in cuticle tanning, we performed RNA interference experiments to decrease the levels of individual phenoloxidases. Normal phenotypes were obtained after dsRNA-mediated transcript depletion for all phenoloxidases tested, with the exception of laccase 2. Insects injected with dsRNA for the laccase 2 gene failed to tan, were soft-bodied and deformed, and subsequently died in a dsRNA dose-dependent fashion. The results presented here support the hypothesis that two isoforms of laccase 2 generated by alternative splicing catalyze larval, pupal, and adult cuticle tanning in Tribolium.exoskeleton ͉ sclerotization ͉ pigmentation ͉ Tribolium castaneum ͉ RNA interference

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“…In the lepidopteran Manduca sexta, the gene Mslac2 showed the higher expression in pharate pupae in comparison to the feeding/wandering larvae and 0-day pupae (Dittmer et al 2004). Similarly, in the coleopteran Tribolium castaneum, the highest levels of TcLac2 transcripts were detected in pharate pupae and pharate adults (Arakane et al 2005).…”

Section: Resultsmentioning

confidence: 98%

“…Its enzymatic activity has been characterized in the integument of Diptera (Barrett & Andersen 1981;Barrett 1987a,b;Binnington & Barrett 1988;Sugumaran et al 1992) and Lepidoptera (Dittmer et al 2009). In addition, the expression of genes encoding laccases has also been described in Diptera (Gorman et al 2008), Lepidoptera (Dittmer et al 2004;Yatsu & Asano 2009), Coleoptera (Arakane et al 2005;Niu et al 2008), and more recently, in Hymenoptera (Elias-Neto et al 2010) and Hemiptera (Futahashi et al 2010(Futahashi et al , 2011.…”

mentioning

confidence: 97%

Expression profile of a Laccase2 encoding gene during the metamorphic molt in Apis mellifera (Hymenoptera,Apidae)

Elias-Neto¹,

Soares²,

Bitondi³

2013

Rev. Bras. entomol.

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Characterization of cDNAs encoding putative laccase-like multicopper oxidases and developmental expression in the tobacco hornworm, Manduca sexta, and the malaria mosquito, Anopheles gambiae

Cited by 178 publications

References 73 publications

Multicopper oxidase-1 is a ferroxidase essential for iron homeostasis in Drosophila melanogaster

Multicopper oxidase-1 is a ferroxidase essential for iron homeostasis in Drosophila melanogaster

Laccase 2 is the phenoloxidase gene required for beetle cuticle tanning

Expression profile of a Laccase2 encoding gene during the metamorphic molt in Apis mellifera (Hymenoptera,Apidae)

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