Egfr and Hypoxia pathways in Apis mellifera queens and workers development - a sistemic approach of their interaction with Juvenile Hormone and Nitric acid

Abstract

The female castes encountered in Apis mellifera colonies differ in their anatomy, physiology and behavior, these differences providing extraordinary efficiency in the realization of caste specifics tasks, such as reproduction (queen) and hive maintenance (workers). The development of each caste depends on the type of diet offered to the female larvae during the growth period. The diet triggers caste-specific physiological responses, especially of the endocrine system, as well as differential gene expression. The honey bee genome annotation project opened the possibility to investigate elements and factors involved in the integration of environmental stimuli with intrinsic responses, especially in terms of epigenetic modifications and signaling pathways, such as insulin (IIS) and target of rapamycin (TOR) signaling, and the hypoxia (HIF) and epidermal growth factor receptor (Egfr) pathways. These, together with juvenile hormone (JH), drive the tissue-specific caste differentiation processes. The aim of this project is to study the integration of the Egfr and HIF signaling pathways and to investigate possible relationships among these signaling modules and the nitric oxide (NO) pathway. The honey bee nitric oxide synthase (NOS) ortholog will be annotated and its transcript levels, as well as those for the genes AmEgfr, analyzed by quantitative RT-PCR during the critical phases of caste development in queen and worker larvae. Additionally, knockdown experiments will be carried out using dsRNA targeting the genes encoding Amegfr and Amsima. RNA of these samples will be used in RNAseq experiments in order to detect influenced genes and their interaction with the well known juvenile hormone influence in the caste differentiation processes of these highly eusocial bees.