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(Reference retrieved automatically from Google Scholar through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Molecular characterization of a cDNA encoding prophenoloxidase and its expression in Apis mellifera

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Author(s):
Lourenço, Anete Pedro [1] ; Zufelato, Maria Salete ; Bitondi, Márcia Maria Gentile ; Simões, Zilá Luz Paulino
Total Authors: 4
Affiliation:
[1] Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto - Brasil
Total Affiliations: 4
Document type: Journal article
Source: Insect Biochemistry and Molecular Biology; v. 35, n. 6, p. 541-552, Jun. 2005.
Field of knowledge: Biological Sciences - Biochemistry
Abstract

Phenoloxidase (PO), a melanin-synthesizing enzyme known to play an important role in insect defense, is found as a zymogen (ProPO) in hemolymph and cuticle, where it is activated by proteolysis. We characterized the first proPO cDNA in an eusocial insect, the Apis mellifera honey bee. The AmproPO cDNA contains an ORF of 2079 bp encoding 693 amino acids, and is composed of 9 exons and 8 introns. Southern blot of digested genomic DNA suggested that only one copy of the proPO gene is present in A. mellifera. The molecular mass of the deduced ProPO and the active enzyme was predicted to be 80.1 and 74.4 kDa, respectively. The calculated pI was 6.28. BLASTp search of the deduced amino acid sequence, and neighbor-joining analysis, showed similarity with ProPOs from other insects, ranging from 47% to 63%. Protein signature analyses revealed four conserved regions, including the two copper binding sites characteristic of arthropod ProPOs. RT-PCR and Southern blot showed the highest amount of AmproPO transcripts in workers whole body, followed by queens and drones. Expression was also detected in hemocytes and integument. Real time RT-PCR showed higher amounts of AmproPO transcripts in adults and older pupae than in younger pupae and larvae, suggesting a function of AmproPO in adult exoskeleton melanization and differentiation. (AU)