title: Differential gene expression underlying ovarian phenotype determination in honey bee, Apis mellifera L., caste development.
abstract: Adult honey bee queens and workers drastically differ in ovary size. This adult ovary phenotype difference becomes established during the final larval instar, when massive programmed cell death leads to the degeneration of 95-99% of the ovariole anlagen in workers. The higher juvenile hormone (JH) levels in queen larvae protect the ovaries against such degeneration. To gain insights into the molecular architecture underlying this divergence critical for adult caste fate and worker sterility, we performed a microarray analysis on fourth and early fifth instar queen and worker ovaries. For the fourth instar we found nine differentially expressed genes (DEGs) with log2FC > 1.0, but this number increased to 56 in early fifth-instar ovaries. We selected 15 DEGs for quantitative PCR (RT-qPCR) analysis. Nine differed significantly by the variables caste and/or development. Interestingly, genes with enzyme functions were higher expressed in workers, while those related to transcription and signaling had higher transcript levels in queens. For the RT-qPCR confirmed genes we analyzed their response to JH. This revealed a significant up-regulation for two genes, a short chain dehydrogenase reductase (sdr) and a heat shock protein 90 (hsp90). Five other genes, including hsp60 and hexamerin 70b (hex70b), were significantly down-regulated by JH. The sdr gene had previously come up as differentially expressed in other transcriptome analyses on honey bee larvae and heat shock proteins are frequently involved in insect hormone responses, this making them interesting candidates for further functional assays.
authors.affiliation: Departamento de Genética, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil. Electronic address: denysecl@usp.br.
authors.forename: Denyse Cavalcante
authors.initials: DC
authors.lastname: Lago
authors.affiliation: Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil; Instituto Federal de Educação, Ciência e Tecnologia de São Paulo, Campus Matão, Rua Estéfano D'avassi, 625, 15991-502 Matão, SP, Brazil. Electronic address: fchumann@gmail.com.
authors.forename: Fernanda Carvalho
authors.initials: FC
authors.lastname: Humann
authors.affiliation: Departamento de Biologia Celular e do Desenvolvimento, Instituto de Ciências Biomédicas, Universidade Federal de Alfenas, Rua Gabriel Monteiro da Silva 700, 37130-000 Alfenas, MG, Brazil. Electronic address: barchuk@unifal-mg.edu.br.
authors.forename: Angel Roberto
authors.initials: AR
authors.lastname: Barchuk
authors.affiliation: Departamento de Puericultura e Pediatria Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil; Universidade Estácio-Uniseb, Rua Abrahão Issa Halach 980, 14096-160 Ribeirão Preto, SP, Brazil. Electronic address: abraham@fmrp.usp.br.
authors.forename: Kuruvilla Joseph
authors.initials: KJ
authors.lastname: Abraham
authors.affiliation: Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil. Electronic address: klaus@fmrp.usp.br.
authors.forename: Klaus
authors.initials: K
authors.lastname: Hartfelder
mesh_terms: D000818:Animals; D001516:Bees / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D007605:Juvenile Hormones / Q000378:metabolism*; D007814:Larva / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010053:Ovary / Q000254:growth & development; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D019476:Insect Proteins; D007605:Juvenile Hormones
keywords: Hexamerin; Honeybee; Juvenile hormone; Ovary transcriptome; Programmed cell death; Short chain dehydrogenase reductase