Project description:In Apis mellifera, the female eggs can develop into workers or queen depending on the diet offered during early development. The outputs of the developed honeybee females are two morphs with particular morphological traits and related physiology. The differential feeding regime experienced by the queen and the worker larvae of the honeybee Apis mellifera shapes a complex endocrine response cascade that ultimately sets up differences in brain morphologies. Herein we report on aspects of brain morphogenesis during larval development and the brain gene expression signature of fourth instar larvae (L4) of both castes, a developmental stage characterized by the greatest differences in juvenile hormone (JH) titers between castes Using results from the hybridization of whole genome-based oligonucleotide arrays with RNA samples from brain of fourth instar larvae honeybees of both castes we present a list of differentially expressed genes.
Project description:In Apis mellifera, the female eggs can develop into workers or queen depending on the diet offered during early development. The outputs of the developed honeybee females are two morphs with particular morphological traits and related physiology. The differential feeding regime experienced by the queen and the worker larvae of the honeybee Apis mellifera shapes a complex endocrine response cascade that ultimately sets up differences in brain morphologies. Herein we report on aspects of brain morphogenesis during larval development and the brain gene expression signature of fourth instar larvae (L4) of both castes, a developmental stage characterized by the greatest differences in juvenile hormone (JH) titers between castes Using results from the hybridization of whole genome-based oligonucleotide arrays with RNA samples from brain of fourth instar larvae honeybees of both castes we present a list of differentially expressed genes. Analysis used one dye-swap combination to compare workers and queens brain development at fourth instar larvae when juvenile hormone titers is higher in queens.
Project description:Adult honey bee queens and workers drastically differ in ovary size. This adult ovary phenotype difference becomes established during the last two larval instars, when massive programmed cell death in the ovaries of worker larvae leads to the degeneration and removal of 95-99% of the ovariole anlagen. The higher juvenile hormone (JH) levels in queen larvae protect their ovaries against such degeneration. To gain insights into the molecular architecture underlying this divergence critical for adult caste fate we performed a microarray analysis contrasting RNA extracts from fourth and early fifth instar queen and worker ovaries. While for the fourth instar we found differential expression (log2FC > 1.0) for only nine genes, the number of differentially represented transcripts (DRTs) increased to 56 in early fifth instar ovaries. From these, 18 had their expression levels further analyzed by real-time PCR (RT-qPCR). For 13 of these the expression differed significantly between queen and worker ovaries at least one time point in development, and interestingly, genes with enzyme functions were overexpressed in workers, while genes related to transcription and signaling were so in queens. For the RT-qPCR confirmed genes we further analyzed their response to JH, revealing a significant up-regulation for two genes, one encoding a short chain dehydrogenase (SDR) and the other heat shock protein 90 (Hsp90). Five other genes, including Hsp60 and hexamerin 70b, were significantly down-regulated by JH. As SDR genes have previously come up as differentially expressed in different transcriptome assays in honey bee larvae, and heat shock proteins are involved in hormone responses, these are interesting candidates for further functional assays.
Project description:Female honeybees are specified as workers or queens based on diet during early development. Workers are essentially sterile with a reduced number of ovarioles and no spermatheca. In the presence of the queen (queen mandibular pheromone) and her brood, worker ovaries are kept in an inactive quiescent state. If the queen is removed, or lost, worker bees are able to sense this change in their environment and their ovaries undergo complete remodeling producing unfertilized haploid eggs that will produce male (drone bees). In this study we analyze gene expression in queen, worker, and laying worker ovaries using RNA-seq and explore differences in the chromatin landscape (focusing on H3K27me3).
Project description:Female honeybees are specified as workers or queens based on diet during early development. Workers are essentially sterile with a reduced number of ovarioles and no spermatheca. In the presence of the queen (queen mandibular pheromone) and her brood, worker ovaries are kept in an inactive quiescent state. If the queen is removed, or lost, worker bees are able to sense this change in their environment and their ovaries undergo complete remodelling producing unfertilised haploid eggs that will produce male (drone bees). In this study we analyse gene expression in queen, worker, and laying worker ovaries using RNA-seq and explore differences in the chromatin landscape (focussing on H3K27me3).