M6A RNA Methylation Modulates Behavioral Plasticity Of Locusts

RNAN6-methyl-adenosine is methylation modification on the sixth nitrogen atom in adenine of RNA.Reversible and dynamic N6-methyl-adenosine as the first found modification on mRNA in eukaryotes,has greatly increased the importance of RNA modification for epigenetic undoubtedly.It had been proven that m6A as the post-transcription modification play an important role in regulating gene expression,translation,and theRNA-protein interactions,In addition,m6A also can affect the stability of the mRNA,microRNAs biogenesis and pluripotency and cell reprogramming and so on.But the m6A biogenesis in the nervous system and its relationship with animal behavior plasticity,is still unknown.The migratory locust(Locusta migratoria),the representative agricultural pests,which has a unique behavioral plasticity:changing phases from a solitary state to a gregarious state depends on the density changing.Two phenotypes have different characteristics on the morphological,physiological and behavior aspects,they can transform into another during a short time.Abundant mRNA expression is variant in this transformation process,obviously,acquired epigenetic modifications leads this phenomenon.Is there RNA m6A methylation exist in the migratory locust?If there is,whether it participate in the transformation between gregarious phase and solitary phase in migratory locust?With these questions,we used the Locust genome database(Locust DB)established by Institute of Zoology,Chinese Academy of Sciences to do the following work:1.We found m6A methyltransferase complex(writers)and demethylase(eraser)and some some reader protein homologous sequences by blastp in the migratory locust genome database using m6A related genes in Human and Mouse,analysis their conserved domains,and amplify whole sequences to prove existence.It indicated that the migratory locusts possess all the key enzymes of m6A methylation system indeed.2.We quantitated the m6A related genes mRNA expression in the migratory locust seven tissuses,and we found all genes express highly in the hemolymph and the brain specifically.In view of the brain is the key to the transformation of migratory locusts,we study m6A related genes mRNA pattern by real-time quantitative PCR in both gregarious and solitary migratory locust,process of phase change under different population densities.The fact that m6A methyltransferase complex revealed higher mRNA levels in the solitary than gregarious Locust,the demethylase is opposite.It indicated that m6A methylation is repressed in gregarious locusts and upregulated in solitarious locusts.Further,we examined the mRNA expression dynamics of m6A related genes during the process of phase change under different population densities.The m6A methyltransferase complex mRNA expression level decreased during the transition from solitaria to gregarious,and increased during the reverse phase transition,the demethylase and reader protein are opposite too.It suggests that m6A may be responsible for the phase change of migratory locust.3.The solitary nymphs transformed into gregarious individuals after the mRNA levels of m6A methyltransferase METTL3、METTL14 were decreased by RNA interference(RNAi).In contrast,the gregarious nymphs transformed into solitary individuals after the mRNA levels of m6A demethylase ALKBH5 were decreased by RNA interference(RNAi).It is confirmed that m6A can regulate the phase change of migratory locust.It is the first time to report the function of m6 in animal behavioral regulation.This research may provide a novel mechanism for the study of Locust behavioral plasticity,and provide theoretical and practical basis for the preestimate and forecast of locust outbreak.