RESUMO
An expressed sequence tag (EST) library was established from the hypopharyngeal glands of Apis cerana. Sixty-six recombinant clones, possessing inserts > 500 bp, were randomly selected and unidirectional sequenced. Forty-two of these (63.6%) were identified as homologues of Major Royal Jelly Proteins families 1, 2, 3, and 4 of A. mellifera (AmMRJP) for which MRJP1 was the most abundant family. The open-reading frame of the MRJP1 homologue (AcMRJP1) was 1299 nucleotides that encoded 433 deduced amino acids with three predicted N-linked glycosylation sites. The AcMRJP1 sequence showed 93% and 90% homologies with nucleotide and deduced amino acid sequences of AmMRJP1, respectively. Two complete transcripts of apisimin, and one and two partial transcripts of alpha-glucosidase and glucose oxidase, were also isolated. In addition, the royal jelly proteins of A. cerana were purified and characterized using Q-Sepharose and Sephadex G-200 column chromatography. The native forms of protein peaks A1, A2, B1, and C1 were 115, 55, 50, and 300 kDa, respectively. SDS-PAGE analysis indicated that A1 and C1 were dimeric and oligomeric forms of the 80 kDa and 50 kDa subunits, respectively. The ratio of the total protein quantities of A1 : A2 : B1 : C1 were 2.52 : 4.72 : 1 : 12.21. Further characterization of each protein, using N-terminal and internal peptide sequencing, revealed that the respective proteins were homologues of MRJP3, MRJP2, MRJP1, and MRJP1 of A. mellifera.
