A Study On The Relationship Between Ecdysone Receptor (EcR), Tyrosine Hydroxylase (TH) And Dopa Decarboxylase (DDC) In Black Spiny Ant

Ecdysteroid receptor(EcR)is the regulatory factor of signaling transduction pathway for ecdysone in insects.In insects,the EcR is currently only known nuclear receptor ligands,its ligand is ecdysteriid hormnones(EH).EH is one of the steroid hormones in invertebrate animals which control the abnormal growth and development of insects,such as metamorphosis and reproduction.Tyrosine hydroxylase(TH)is the first enzyme in neurotransmitter biosynthesis of dopamine(DA)and other catecholamines(CAs).It is also a speed limit enzyme.Catecholamine substances regulate the animal's plant nerve reflex,behavior,cycle control,cognition,endocrine function,exercise,pain,reward and vigilance.Dopa decarboxylase(DDC)is one of the important enzymes in the biosynthesis pathway of catecholamine,which has many biological functions.DDC plays an extremely important role in insect growth and development,which is related to the melanogenesis of insects,and participates in the process of the insects molting.In addition,DDC also participates in the physiological activities of insect color formation,development and lifespan.Polyrhachis vicina Roger is the representative of social insect in hymenoptera,which life cycle is divided into four main stages:egg,larva,pupa and adult.According to different morphology,behavior and social division of labor,adult is divided into three castes such as queens,males and workers,and each caste has a clear social division of labor.P.vicina is adopted by Ministry Of Health P.R.China as only the ant which can be used both in the medicine and the health care food.It's also a good study material in social insect of growth and gene regulatory mechanisms.We have studied the normal expression of PvEcR,PvTH,PvDDC in P.vicina and oral fooding PvEcR dsRNA showed that PvDDC and PvTH respectively with PvEcR has certain correlation.Based on the three genes have important influence for the insects growth,so we use RNAi technology i.e.oral fooding PvEcR dsRNA continue to investigate the relationship of those three genes,,which can lay a theoretical foundation for social insect caste differentiation regulatory mechanism study.The results are as follows:1.Oral feeding by PvEcR RNAi technology of P.vicina adults,found three castes of adult including weight,head width,length all have certain changes,abodomen swollen and deormed,larvae from round transparent turn into black shrivel,pupa unnormal molting.So we speculated PvEcR may have directly influences on the normal growth and development of P.vicina.2.qRT-PCR technique was used to detect PvTH and PvDDC expression including the whole and the worker head,thorax,abodomen in P.vicina castes before and after PvEcR RNAi on the mRNA levels.The results showed that PvTH and PvDDC expression of different development stages of ant bodys mainly presented down-regulated status,only males expression up-regulated.According to the state of PvTH and PvDDC change and combined with previously results of the laboratory I consided that there was some correlation betwee PvTH and PvEcR which may directectly influence the abdomen and chest development in the ants.3.The Western-blot technique was used to detecte protein level expressions of P.vicina including three castes adult expressions,workers head,thorax and abdomen parts.After comparing PvTH and PvDDC expression,we found that there are differences between them,and consistent with the level of mRNA expression,the results further show that the correlation between PvTH and PvDDC.4.IHC and ISH techniques were used to detected mRNA and protein levels in different castes of P.vicina brain and abdominal sections.The results showed that after PvEcR-RNAi,PvTH and PvDDC expression were down-regulated,the brain mainly exhibited on the mushroom bodies,pons body,central complex,optic lobe and olfactory lobe,the abdomen was mainly concentrated in the reproductive cavity,spermatheca and fat body,and accessory gland of male ants also had positively relatively weak expression.From those we speculate that PvTH and PvDDC are related to PvEcR in functions,and influence P.vicina behaviors of learning and memory as well as abdominal reproductive behaviors.5.The results revealed the interference process on the sixth day time as an important time node,the expression change all start from the sixth day,we suggest that sixth day can be as a key point for development of P.vicina.