Global gene expression profiling of Homarus americanus (Crustacea) larval stages during development and metamorphosis

Abstract

Homarus americanus has a life history that is similar to other arthropods, including a pelagic larval phase and a benthic adult phase. The larval phase is divided into three morphologically distinct stages, followed by metamorphosis to the post-larval phase. H. americanus larval development has been studied previously, although the molecular mechanisms that regulate the consequent changes are not fully elucidated. This study is the first to use an oligonucleotide microarray to investigate global gene expression during H. americanus larval development. Stage-specific gene expression profiles of larvae and postlarvae from two-year classes were assessed. We found the expression levels of 1851 genes to be significantly different among larval stages. Functional annotations indicated that various differentially expressed genes were involved with immune function, energy regulation, and development. Ten target genes of interest were selected for expression verification using RT-qPCR. Two Phosphoenolpyruvatecarboxykinases, Argonaute 2, Ecdysone-inducible protein 75, and Procollagen-lysine 2-oxoglutarate 5-dioxygenase 3, had significantly different expression (p < 0.05) among stages. These genes are involved in translation regulation, gene expression, morphological development and energy metabolism. This study provides a foundation for future investigations regarding signaling, morphological remodeling, energy metabolism, and the immune system as they pertain to larval development.

Keywords:

• microarray
• RT-qPCR
• Decapoda
• lobster

Acknowledgments

The authors would like to recognize the contributions of the late Dr. David Towle of the Mount Desert Island Biological Laboratory to this research. David’s collaboration during the original sequencing of the lobster ESTs and his help in generating the H. americanus microarray version 1.0 were essential. David was an excellent mentor whose passion for marine genomics and his collegial nature will be sorely missed. The authors thank Dr Dounia Daoud, Homarus Inc./Coastal Zones Research Institute with identification and staging of lobster larvae. Funding for the AVC Lobster Science Centre is provided from multiple sources including: private sector companies, fisher organizations, First Nations and Provincial and Federal Government agencies. Major funding was provided by the Atlantic Innovation Fund (round V) through the Atlantic Canada Opportunities Agency (ACOA) and the PEI Atlantic Shrimp Corporation Inc.