The expression and function of miR-124 in the three castes of the honeybee Apis mellifera
Author of the article:XUN Li-Jie** ZHANG Xue-Wen WANG Yan-Hui***
Author's Workplace：Institute of Sericulture and Apiculture, Yunnan Academy of Agricultural Sciences, Mengzi 661101, China
Key Words：miR-124, neural development, molecular evolution, homology, gene ontology analysis, pathway analysis
Abstract：
[Objectives] miR-124 is related to the development of the nervous system and is expressed specifically in the brains of multicellular animals. This study was designed to verify whether expression of miR-124 is restricted to the brain in all three castes of the honeybee Apis mellifera, to analyze the expression of this gene in the three castes, and to provide a foundation for studying the function of miR-124 in the honeybee. [Methods] Real-time Polymerase Chain Reaction (known as stem-loop RT-qPCR assay) was used to detect the expression of miR-124 in the head and other parts of honeybees from each caste using stem-loop primer reverse transcription miRNA. Neighbor joining miR-124 phylogenetic trees were constructed and the software package BioEdit used to analyze the homology of mature miR-124 sequences. A search for the target gene of miR-124 in the honeybee was then conducted and the function of the putative target gene analyzed. [Results] miR-124 was highly expressed in the heads of honeybees from all three castes but was more highly expressed in workers than drones and least expressed in queens. miR-124 expression in body parts other than the head was negligible in all three castes. In many species, the minimum and maximum homology of miR-124 reached 82.6% and 100%, respectively. Ninety-six potential miR-124 target genes were identified in the honeybee, forty-five of which were annotated. Functional classification revealed that multiple miR-124 target genes are involved in neural development and regulation. [Conclusion] miR-124 expression is predominantly confined to the head in all three honeybee castes where it is more highly expressed in workers than drones and least expressed in queens. Worker's brains are more developed than those of drones and the brains of queens are the least developed. We suspect that the observed variation in the expression of miR-124 among honeybee castes is related to the level of brain development in each caste, and ultimately to the different roles that each caste plays in the hive.