Age And Behaviour-related Expression Levels Of 6 MiRNAs In The Brain Of Apis Mellifera Ligustica Workers

The honeybee(Apis mellifera ligustica)is an eusocial insect,its workers show age-dependent behavioral changes,and the behaviour of workers is very flexibility,they can change their behavioural development according to the colony needs.Micro RNAs(miRNAs)are a class of 18-24-nucleotide(nt),endogenously initiated,small noncoding,single stranded RNAs that can regulate target gene expression via either translational repression or m RNA degradation by combining with target m RNA complementarily.The mechanisms of the behavioral transition have been the hot research topic.In this study,we investigated the expression levels of 6 candidate miRNAs,i.e.,let-7,miR-13 b,miR-31 a,miR-210,miR-275,miR-279 andmiR-279,in A.mellifera ligustica workers at different age(4,8,12,17,22,26 and 30 day-old)by real-time quantitative PCR(RT-qPCR).This study also established the single-cohort colony to test the expression levels of let-7,miR-13 b and miR-279 between12-and30-day-old age-matched nurses and foragers by RT-qPCR and northern blot.All obove are for screening out the miRNA may be involved with the behavioral transition in honeybee.The following is the main research content:1.The expression levels of 6 candidate miRNAs in workers at different ageThe expression of let-7,miR-13 b and miR-279 in workers showed a high degree of temporal specificity:the expression level of let-7 was reduced with the increasing age of the workers and tended to be stable after 17 day-old.The expression level of miR-13 b increased with age of workers and kept stable in 26 and 30 day-old workers.The expression level of miR-279 was near tothe normal distribution,peaked in the 12day-old workers and kept stable in over 17 day-old workers.The expression of other 3miRNAs(miR-31 a,miR-210,miR-275)showed no temporal specificity[1].2.The expression levels of 3 miRNAs in age-matched nurses and foragerslet-7 expressed extremely up-regulated both in 12-and 30-day-old nurses compared with the age-matched foragers(P<0.01);The expression level of miR-13 b was significantly higher in nurses than foragers at 12-day-old(P<0.05),while it was expressed at significantly higher levels in foragers than nurses at 30-day-old(P<0.05);Then miR-279 was expressed at extremely remarkably higher levels in nueses than foragers at 12-day-old(P<0.01),and the expression level of miR-279 was remarkably higher in nurses than foragers at 30-day-old(P<0.05).Northern blot analysis results are consistent with the RT-qPCR.The expression levels of let-7 and miR-279 in the brain of workers showed significant regularity and temporal-behavioural specificity in workers.