A chitin-like component in Aedes aegypti eggshells, eggs and ovaries

Moreira, Mônica F.; Santos, Amanda Souza; Marotta, Humberto; Mansur, Juliana F.; Ramos, Isabela; Machado, Ednildo A.; Souza, Gustavo H. M. F.; Eberlin, Marcos N.; Kaiser, Carlos R.; Kramer, Karl J.; Muthukrishnan, Subbaratnam; Vasconcellos, Ana Maria H.

doi:10.1016/j.ibmb.2007.07.017

Cited by 100 publications

(74 citation statements)

References 59 publications

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“…Even though the Tribolium eggshell has not been directly analyzed for chitin, we speculate that it may contain chitin or a related material. Consistent with this notion is the recent report that a chitin-like substance is present in mosquito eggshells, eggs, and ovaries (13).…”

Section: Discussionsupporting

confidence: 54%

Functional specialization among insect chitinase family genes revealed by RNA interference

Zhu

Arakane

Beeman

et al. 2008

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

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The biological functions of individual members of the large family of chitinase-like proteins from the red flour beetle, Tribolium castaneum (Tc), were examined by using gene-specific RNAi. One chitinase, TcCHT5, was found to be required for pupal-adult molting only. A lethal phenotype was observed when the transcript level of TcCHT5 was down-regulated by injection of TcCHT5-specific dsRNA into larvae. The larvae had metamorphosed into pupae and then to pharate adults but did not complete adult eclosion. Specific knockdown of transcripts for another chitinase, TcCHT10, which has multiple catalytic domains, prevented embryo hatch, larval molting, pupation, and adult metamorphosis, indicating a vital role for TcCHT10 during each of these processes. A third chitinase-like protein, TcCHT7, was required for abdominal contraction and wing/elytra extension immediately after pupation but was dispensable for larval-larval molting, pupation, and adult eclosion. The wing/elytra abnormalities found in TcCHT7-silenced pupae were also manifest in the ensuing adults. A fourth chitinaselike protein, TcIDGF4, exhibited no chitinolytic activity but contributed to adult eclosion. No phenotypic effects were observed after knockdown of transcripts for several other chitinase-like proteins, including imaginal disk growth factor IDGF2. These data indicate functional specialization among insect chitinase family genes, primarily during the molting process, and provide a biological rationale for the presence of a large assortment of chitinase-like proteins.functional genomics ͉ gene family ͉ molting defects ͉ wing abnormalities C hitinases (␤-1,4-poly-N-acetylglucosaminidase; EC 3.2.1.14)are members of the O-glycoside hydrolase superfamily and are found in many species, including microbes, plants, insects, and mammals (1). Insect chitinases, which belong to family 18 glycosylhydrolases, have been detected in molting fluid and gut tissues and are predicted to mediate the digestion of chitin present in the exoskeleton and peritrophic membrane (PM) in the gut to chitooligosaccharides (2, 3). Genes and cDNAs encoding insect chitinases have been identified and characterized from several lepidopteran, dipteran, and coleopteran insects (4-6). Even though only one (or occasionally two) chitinase gene had been previously identified in studies involving many insect species, database searches of fully sequenced genomes from Drosophila, Anopheles, and, more recently, Tribolium, have revealed that each of these insects has a rather large family of genes encoding chitinase and chitinase-like proteins with 16-23 members, depending on the species (refs. 7 and 8 and unpublished data). Based on amino acid sequence similarity and phylogenetic analysis, insect chitinase family proteins have been classified into five or possibly more groups (7,8). From currently available data on a large number of biochemically characterized insect chitinases, we have hypothesized that many and perhaps all group I insect chitinases are involved in chitinolysis associated wit...

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Section: Discussionsupporting

confidence: 54%

Functional specialization among insect chitinase family genes revealed by RNA interference

Zhu

Arakane

Beeman

et al. 2008

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

Self Cite

235

287

View full text Add to dashboard Cite

show abstract

“…Therefore, this domain may function as a chitin-binding domain. A chitin-like material has also been identified in the ovarian follicular epithelial cells of the mosquito Aedes aegypti (Moreira et al, 2007). This correlates with the expression of AgMCO1-3 in the ovaries of A. gambiae.…”

Section: Discussionmentioning

confidence: 67%

Insect multicopper oxidases: Diversity, properties, and physiological roles

Dittmer

Kanost

2010

Insect Biochemistry and Molecular Biology

117

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“…The failure of the eggs to hatch may reflect a lack of mechanical strength of the newly synthesized embryonic cuticle. Moreira et al (2007), however, identified a chitin-like component in A. aegypti eggshells. When T. castaneum eggs were stained with FITC (fluorescein isothiocyanate)-conjugated chitin-binding protein (Arakane et al, 2005), fluorescence was observed in wild-type eggshells but not in those from dsTcCHS-A-treated females (unpublished data).…”

Section: Resultsmentioning

confidence: 91%