Identification of a juvenile hormone esterase-like gene in the honey bee, Apis mellifera L.--expression analysis and functional assays.
Tight control over circulating juvenile hormone (JH) levels is of prime importance in an insect's life cycle. Consequently, enzymes involved in JH metabolism, especially juvenile hormone esterases (JHEs), play major roles during metamorphosis and reproduction. In the highly eusocial Hymenoptera, JH has been co-opted into additional functions, primarily in the development of the queen and worker castes and in age-related behavioral development of workers. Within a set of 21 carboxylesterases predicted in the honey bee genome we identified one gene (Amjhe-like) that contained the main functional motifs of insect JHEs. Its transcript levels during larval development showed a maximum at the switch from feeding to spinning behavior, coinciding with a JH titer minimum. In adult workers, the highest levels were observed in nurse bees, where a low JH titer is required to prevent the switch to foraging. Functional assays showed that Amjhe-like expression is induced by JH-III and suppressed by 20-hydroxyecdysone. RNAi-mediated silencing of Amjhe-like gene function resulted in a six-fold increase in the JH titer in adult worker bees. The temporal profile of Amjhe-like expression in larval and adult workers, the pattern of hormonal regulation and the knockdown phenotype are consistent with the function of this gene as an authentic JHE.
Mackert
Aline
A
Departamento de Genética, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil. mackert@rge.fmrp.usp.br
do Nascimento
Adriana Mendes
AM
Bitondi
Márcia Maria Gentile
MM
Hartfelder
Klaus
K
Simões
Zilá Luz Paulino
ZL
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001516:Bees / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D043182:Carboxylesterase / Q000737:chemistry; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry / Q000235:genetics*; D004441:Ecdysterone / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D006458:Hemolymph / Q000187:drug effects / Q000378:metabolism; D006608:Hierarchy, Social; D007605:Juvenile Hormones / Q000494:pharmacology; D008018:Life Cycle Stages / Q000187:drug effects; D008969:Molecular Sequence Data; D034622:RNA Interference / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020539:Sequence Analysis, Protein; D014819:Vitellogenins / Q000378:metabolism
D007605:Juvenile Hormones; D012333:RNA, Messenger; D014819:Vitellogenins; D004441:Ecdysterone; D002265:Carboxylic Ester Hydrolases; C038003:juvenile hormone esterase; D043182:Carboxylesterase