Both UDP N-acetylglucosamine pyrophosphorylases of Tribolium castaneum are critical for molting, survival and fecundity

Yasuyuki Arakane, Marilyn C. Baguinon, Sinu Jasrapuria, Sujata Chaudhari, Alison Doyungan, Karl J. Kramer, Subbaratnam Muthukrishnan, Richard W. Beeman

Research output: Contribution to journalArticlepeer-review

37 Scopus citations

Abstract

A bioinformatics search of the genome of the red flour beetle, Tribolium castaneum, resulted in the identification of two genes encoding proteins closely related to UDP-N-acetylglucosamine pyrophosphorylases (UAPs), which provide the activated precursor, UDP-N-acetylglucosamine, for the synthesis of chitin, glycoproteins and glycosylphosphoinositide (GPI) anchors of some membrane proteins as well as for the modification of other substrates. This is in contrast to other arthropods whose genomes have been completely sequenced, all of which have only a single copy of this gene. The two T. castaneum UAP genes, TcUAP1 and TcUAP2, share both nucleotide and amino acid sequence identities of about 60%. RT-PCR analysis revealed that the two genes differ in their developmental and tissue-specific patterns of expression. RNA interference (RNAi) indicated roles for TcUAP1 and TcUAP2 at the molt and intermolt stages, respectively: RNAi for TcUAP1 resulted in specific arrest at the larval-larval, larval-pupal or pupal-adult molts, depending on time of injection of double-stranded RNAs, whereas RNAi for TcUAP2 prevented larval growth or resulted in pupal paralysis. Analysis of elytral cuticle indicated loss of structural integrity and chitin staining after RNAi for TcUAP1, but not after RNAi for TcUAP2. Loss of peritrophic matrix (PM)-associated chitin was also observed following RNAi for TcUAP1, but not after RNAi for TcUAP2. Down-regulation of transcripts for either TcUAP gene at the mature adult stage resulted in cessation of oviposition in females, as well as fat body depletion and eventual death in both sexes. These results demonstrate that both TcUAP genes are critical for beetle development and survival, but that only TcUAP1 is clearly associated with synthesis of cuticular or PM chitin. However, both of these genes appear to have additional critical role(s) unrelated to chitin synthesis, presumably in the glycosylation of proteins and/or secondary metabolites.

Original languageEnglish (US)
Pages (from-to)42-50
Number of pages9
JournalInsect Biochemistry and Molecular Biology
Volume41
Issue number1
DOIs
StatePublished - Jan 2011
Externally publishedYes

Keywords

  • Chitin
  • Cuticle
  • Peritrophic matrix
  • Tribolium castaneum
  • UDP-N-acetylglucosamine
  • UDP-N-acetylglucosamine pyrophosphorylase

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Insect Science

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