In vitro secretion of ecdysteroid-dependent proteins and of a 70 kDa subunit reactive to anti-prophenoloxidase serum by Apis mellifera integumentNínive A. Colonelloa, Maria Salete Zufelatoa, Zilá L.P. Simõesa, b and Márcia M.G. Bitondia, b
a Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Departamento de Biologia, Av. Bandeirantes 3900, 14040-901 Ribeirão Preto, SP, Brasil
b Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Departamento de Genética, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brasil
(Received 1 October 2002; revised 18 December 2002; accepted 2 January 2003)
A tissue culture approach was used to monitor changes in protein secretion by integuments from Apis mellifera along the pupal stage. A dramatic change in epidermal protein secretion was correlated with the variation in endogenous ecdysteroid from a low level at the beginning of the pupal stage to a maximum level in the middle of this stage. Only a fraction of these proteins, however, turned out to be directly regulated by ecdysteroids when we exposed cultured integument to 20-hydroxyecdysone. An antiserum raised against a honey bee activated prophenoloxidase (proPO) found in hemolymph recognized a 70 kDa subunit in pupal integument incubations, strongly suggesting that honey bee epidermis synthesizes a genuine proPO. The 70 kDa subunit is not developmentally regulated by the ecdysteroid titer. Its constitutive expression throughout the pupal stage makes it difficult to reconcile the function of this protein with progressive cuticle pigmentation in late honey bee pupae.
Key words: Apis mellifera / integument / epidermis / cuticle / cuticular protein / prophenoloxidase
Correspondence and reprints: Márcia M.G. Bitondi
© INRA, EDP Sciences, DIB, AGIB 2003