A honeybee storage protein gene, hex 70a, expressed in developing gonads and nutritionally regulated in adult fat body.
In preparing for metamorphosis, insect larvae store a huge amount of proteins in hemolymph, mainly hexamerins. Out of the four hexamerins present in the honeybee larvae, one, HEX 70a, exhibited a distinct developmental pattern, especially since it is also present in adults. Here, we report sequence data and experimental evidence suggesting alternative functions for HEX 70a, besides its well-known role as an amino acid resource during metamorphosis. The hex 70a gene consists of 6 exons and encodes a 684 amino acid chain containing the conserved hemocyanin N, M, and C domains. HEX 70a classifies as an arylphorin since it contains more than 15% of aromatic amino acids. In the fat body of adult workers, hex 70a expression turned out to be a nutrient-limited process. However, the fat body is not the only site for hex 70a expression. Both, transcript and protein subunits were also detected in developing gonads from workers, queens and drones, suggesting a role in ovary differentiation and testes maturation and functioning. In its putative reproductive role, HEX 70a however differs from the yolk protein, vitellogenin, since it was not detected in eggs or embryos.
Martins
Juliana Ramos
JR
Faculdade de Medicina de Ribeirão Preto, Departamento de Genética, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
Nunes
Francis Morais Franco
FM
Simões
Zilá Luz Paulino
ZL
Bitondi
Márcia Maria Gentile
MM
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D001516:Bees / Q000378:metabolism*; D015153:Blotting, Western; D017931:DNA Primers / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D005216:Fat Body / Q000378:metabolism*; D040461:Gene Components; D006066:Gonads / Q000378:metabolism*; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism*; D007814:Larva / Q000378:metabolism; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012741:Sexual Maturation
D000596:Amino Acids; D017931:DNA Primers; D019476:Insect Proteins; C041137:storage proteins, Insecta