| MicroRNA(miRNA)is a class of noncodingRNA that has highly conserved seed area,which is about 22-24 nucleotides,and exists in a variety of organisms.It usually functions by targeting the 3?UTR of mRNA with base pairing after transcription,and regulates the target gene by degradating mRNA or inhibiting its translation.At present,the miRN A researches of fish are majoring in tissue sequencing,expression identification,differential expression analysis and bioinformation analysis.These research results provide a quantity of basic dataes for miRN A function research in fish,but it?s more important to know deeply about the function and the mechanism of miRN A in fish.As an important vertebrate,the researches about miRNA in fishare less.This paper first has a study on the effects of VE deficiency on liver miRN A expression profile of N ile tilapia,and then chosen miR-155 and study its function in fish tissue and cell.The major results are as follows:1.Effects of VE deficie ncy on liver miRNA expression profile of Nile tilapia.Taking tilapia as the experiment animal,studyi ng on effects of VE deficiency and normal on liver miRNA expression profile of Nile tilapia.The r esult s hows there are 340 miRNAs expression are signif icantly c hanged,among them,197 miRNAs up regulated,143 miRNAs do wn regulated.The immune-related miR-155 was up regulated i n VE deficiency group,and VE deficiencyalso resulted i n the up reguation of miR-133 b,miR-462 and miR-731,t hese miRNAs play important roles in anti oxidation and immunity response.Through GO and KEGG enrichment analysis,we conclude VE ca n participate i n the physiological process of various diseases due to its antioxidant and immunity functi on.2.Study on the function of miR-155 i n fish.First,taki ng carp and catfis h as the experiment animal,i njecti ng wit h ago miR-155 and agomiR-NC respecti vel y,and then stimulated with LPS,last detecting the expression of miR-155 and immune cytokines of the liver,spleen and head-kidney.In carp,miR-155 resulted in the down regulation of IFN-?1 expression and up regulation of IL-1? in every tissue.For TNF-? in carp,it was up regulated in liver but down regulated in spleen and head-kindey.Also,JAK1 was down regulated in head kindey,which means miR-155 can play role in immunity thro ugh JAK/STAT singnaling pathway.However,in channel catfish,we detected the expression of miR-155 and immune cytokines of the liver,spleen and head-kidney after 12 h,24h and 48 h.The result shows some differences between catfish from carp,but miR-155 has a certain of impacts on IFN-?1,IL-1?,TNF-? etc.miR-155 can significantly up regulate the expression of TNF-?,and down regulate the expression of SOCS1 after 12 h and 24 h.Based on the fish tissue experiment,we had a further study about miR-155 incell.Taking C LC as experiment cell,transfecting with miR-155 mimics and NC respectively,and then injecting with LPS,detecting the expression of immune cytokines.The result shows that those significantly changed factors in fish are affected by miR-155 in clc,including IFN-?1,IL-6,IL-10 and TNF-?.To further research the function of miR-155,we have a study on the SOCS1 gene that significantly changed in fish tissue.Using double luciferase report experiment to identify target gene,the result shows SOCS1 was a target gene of miR-155 i n c hannel catfish.This stud y shows VE deficienc y have effects on the of liver miRNA e xpressi on profile of Nile tilapia,among them,some of c hanged miRNAs participated in the antioxidant a nd immunity regulation process in or ganism.From the research results of fish a nd cell,the results s ho w that miR-155 ca n regulate t he expressi on of I F N-?1,TNF-?,etc immune cell cytokines,eve n socs1 wan a tar get gene of miR-155. |
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