Regulation of chitin synthesis in the larval midgut of Manduca sexta

Zimoch, Lars; Hogenkamp, David G.; Kramer, Karl J.; Muthukrishnan, Subbaratnam; Merzendorfer, Hans

doi:10.1016/j.ibmb.2005.01.008

Cited by 93 publications

(79 citation statements)

References 48 publications

(73 reference statements)

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“…The PM also serves as a barrier for ODV infection of the midgut epithelial cells. Chitin in the PM is synthesized by chitin synthase, which is membrane bound on midgut epithelial cells, and polymerizing chitin is secreted at the apical side of the epithelial cells to be incorporated into the PM (38,39). Therefore, the potential chitin-binding ability of P95 might be involved in mediating interactions between ODVs and PM or between ODVs and epithelial cells, the target cells of ODV infection.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Novel Components of the Baculovirus Per Os Infectivity Factor Complex

Peng

Lent

Boeren

et al. 2012

J Virol

126

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Baculovirus occlusion-derived virus (ODV) infects insect midgut cells under alkaline conditions, a process mediated by highly conserved per os infectivity factors (PIFs), P74 (PIF0), PIF1, PIF2, PIF3, PIF4, and PIF5 (ODV-E56). Previously, a multimolecular complex composed of PIF1, PIF2, PIF3, and P74 was identified which was proposed to play an essential role during ODV entry. Recently, more proteins have been identified that play important roles in ODV oral infectivity, including PIF4, PIF5, and SF58, which might work in concert with previously known PIFs to facilitate ODV infection. In order to understand the ODV entry mechanism, the identification of all components of the PIF complex is crucial. Hence, the aim of this study was to identify additional components of the PIF complex. Coimmunoprecipitation (CoIP) combined with proteomic analysis was used to identify the components of the Autographa californica multiple nucleopolyhedrovirus (AcMNPV) PIF complex. PIF4 and P95 (AC83) were identified as components of the PIF complex while PIF5 was not, and this was confirmed with blue native PAGE and a second CoIP. Deletion of the pif4 gene impaired complex formation, but deletion of pif5 did not. Differentially denaturing SDS-PAGE further revealed that PIF4 forms a stable complex with PIF1, PIF2, and PIF3. P95 and P74 are more loosely associated with this complex. Three other proteins, AC5, AC68, and AC108 (homologue of SF58), were also found by the proteomic analysis to be associated with the PIF complex. Finally the functional significance of the PIF protein interactions is discussed.

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Section: Discussionmentioning

confidence: 99%

Characterization of Novel Components of the Baculovirus Per Os Infectivity Factor Complex

Peng

Lent

Boeren

et al. 2012

J Virol

126

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“…This is quite surprising because IDGFs are thought to be involved in cell proliferation and/or differentiation (23) but not in ecdysis. It is possible that this chitinase-like protein is involved in tracheal proliferation, which is known to occur at this stage (24). Of particular interest is that knockdown of Tribolium IDGF2 does not result in any altered phenotype compared with the control.…”

Section: Discussionmentioning

confidence: 99%

Functional specialization among insect chitinase family genes revealed by RNA interference

Zhu

Arakane

Beeman

et al. 2008

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

234

287

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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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“…Chitin is an insoluble structural polysaccharide that is important as a supporting element in arthropod exoskeleton (Neville et al, 1976), fungal and bacterial cell walls (Debono and Gordee, 1994;Gomaa, 2012), microfilaria sheath (Araujo et al, 1993) and the lining of the digestive tracts of many arthropods (Souza-Neto et al, 2003;Zimoch et al, 2005;Khajuria et al, 2010). Arthropod development and morphogenesis rely on remodeling chitin and in the process requires chitin synthases and chitinases to control this process (Merzendorfer and Zimoch, 2003).…”

Section: Research Articlementioning

confidence: 99%

Dual silencing of long and short Amblyomma americanum acidic chitinase forms weakens the tick cement cone stability

Kim

Curran

Mulenga

2014

Journal of Experimental Biology

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This study demonstrates that Amblyomma americanum (Aam) constitutively and ubiquitously expresses the long (L) and short (S) putative acidic chitinases (Ach) that are distinguished by a 210 base pair (bp) deletion in AamAch-S. Full-length AamAch-L and AamAch-S cDNA are 1959 and 1718 bp long, containing 1332 and 1104 bp open reading frames that code for 443 and 367 amino acid residues proteins with the former predicted to be extracellular and the latter intracellular. Both AamAch-L and AamAch-S mRNA are expressed in multiple organs as revealed by qualitative RT-PCR analysis. Furthermore, quantitative reverse transcription polymerase chain reaction analysis revealed that AamAch-L mRNA was downregulated in the mid-gut, but was unchanged in the salivary gland and in other organs in response to feeding. Of significant interest, AamAch-L and/or AamAch-S functions are probably associated with formation and/or maintenance of stability of A. americanum tick cement cone. Dual RNA interference silencing of AamAch-L and/or AamAch-S mRNA caused ticks to loosely attach onto host skin as suggested by bleeding around tick mouthparts and ticks detaching off host skin with a light touch. AamAch-L may apparently encode an inactive chitinase as indicated by Pichia pastoris-expressed recombinant AamAch-L failing to hydrolyse chitinase substrates. Unpublished related work in our laboratory, and published work by others that found AamAch-L in tick saliva, suggest that native AamAch-L is a non-specific immunoglobulin binding tick saliva protein in that rAamAch-L nonspecifically bound rabbit, bovine and chicken non-immune sera. We discuss findings in this study with reference to advancing knowledge on tick feeding physiology.

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Regulation of chitin synthesis in the larval midgut of Manduca sexta

Cited by 93 publications

References 48 publications

Characterization of Novel Components of the Baculovirus Per Os Infectivity Factor Complex

Characterization of Novel Components of the Baculovirus Per Os Infectivity Factor Complex

Functional specialization among insect chitinase family genes revealed by RNA interference

Dual silencing of long and short Amblyomma americanum acidic chitinase forms weakens the tick cement cone stability

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