|Lattorf H., Michael|
Submitted to: Insect Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2006
Publication Date: 11/1/2006
Citation: Cristino, A.S., Nunes, F.M., Lobo, C.H., Bitondi, M.M., Simoes, Z.L., Lattorf H., M.G., Moritz, R.F., Evans, J.D., Costa, L.F., Hartfelder, K. 2006. Caste development and reproduction - a genome-wide analysis of hallmarks of insect eusociality. Insect Molecular Biology. 15:703-714. Interpretive Summary: Honey bees are key components of U.S. agriculture, diversifying the food supply and generating over $15 billion annually through pollination effects, honey, and other hive products. This project is focused on the production of healthy honey bee queens. During honey bee development, specific genes are activated to help push larvae to become either queens or workers. Here we describe these genes, showing that queens activate genes biased toward high metabolism, and that both queens and workers activate distinct sets of genes that fit with their different diets. This information can aid in bee nutrition decisions made by beekeepers, and in research exploring the colony and management factors that result in robust, productive queens. The net result will be to ensure queen longevity and to improve and maintain excellent bee stock.
Technical Abstract: The morphologically divergent queen and worker castes and their associated differences in fertility have made the honey bee a long time model system for studies on the development of alternative phenotypes. The honey bee genome sequence now provides the platform for functional genomic approaches to this question. EST libaries for caste-specific gene expression during queen/worker differentiation in the last larval instar provided the database for a Gene Ontology based annotation of caste-specifically expressed genes. This revealed that worker genes are functionally much better defined than queen genes, calling into question the idea that the queen caste represents the non-social female bee prototype. Furthermore, metabolic regulation emerged as a major theme in caste development, with queens and workers showing a split in gene expression patterns for oxidoreductases versus hydrolases. AlignACE motif searches in upstream regions of these case genes revealed the presence of group-specific motifs that could allow for coregulated gene expression, thus providing an entry to putative cis-regulatory networks for caste development. Genes involved in honey bee reproduction were annotated in searches against Drosophila orthologs, revealing a high degree of conservation for meiosis-associated genes, whereas some key elements of signaling pathways for egg and embryonic axes either did not show up as clear orthologs (bag of marbles, gurken, torso), or are completely lacking (trunk) in the bee genome. Honey bee vitellogenin, a major determinant of female fertility and longevity, turned out to be much more related to vitellogenins from other insects, than to the Drosophila yolk proteins.