The Discovery Of DNA-recognition Receptor CGAS Signaling In And Out Of The Nucleus And Its Function In Innate Immunity

External pathogens cause the body to produce some more serious disease can lead to death,innate immunity can help the body's resistance to the outside world's attack on the pathogen,numerous biological defenses of the host inprotection,innate immunity is the first,so innate immunity in protecting host defense outside pathogens has the extremely important status When pathogens contact and invade the body,some substances in the body can quickly identify the alien molecules,produce interferon,actively "eradicate"the alien,to ensure their own safety.At present,researchers have found that there are a number of molecular recognition outside invading pathogens,will identify the signal through a certain way to transfer to the downstream signaling molecule in cells,make innate immunity is then activated and protect the host's role,so the researchers will take this class can identify the pathogen signal molecules called Pattern Recognition Receptors(PRR.the Pattern recognition receptor).The pattern recognition receptor can recognize a variety of pathogens.which can rapidly activate the downstream effector molecules to induce the production of IFN.cGAS is also a pattern recog,nition receptor,and its way of activating innate immunity is also to recognize invading pathogens.However.cGAS can recognize not only the DNA molecules entering the outside world.but also the DNA molecules belonging,to the cell itself.The universality of cGAS as a DNA recognition receptor is of great significance to the development of innate immunity.cGAS is called cyclic Gmp-Amp synthase and is a member of the nucleotide transferase family.cGAS can recognize the DNA entering from the outside,produce the second messenger 2 '3'-cGAMP,activate the cGAS-STMG pathway.and induce the expression of type 1 interferon and other immune response genes.cGAS mostly exists in the cytoplasm,and recent studies have shown that cGAS also exists in the nucleus.But the molecular weight of cGAS exceeds the upper limit for active transport in and out of the nucleus.So ho,w does cGAS get into the nucleus?And how do you get from the nucleus into the cytoplasm?Does cGAS have nuclear export signal and nuclear localization signal?What are the effects of cGAS entry and exit on its biological function in innate immunity?These questions require further study.Based on the above scientific questions,based on the experimental phenomenon of cGAS observed in both the nucleus and cytoplasm.this experiment conducted bioinformatics analysis on the full length sequence of cGAS protein,and found the possible nuclear localization signal sequence(299KRKR-302)and nuclear export signal sequence(169LEKLKL174).Then possible signal sequences were mutated,mutated and wild-type were transfected into cells,and the hypothesis was verified by experiments such as nuclear cytoplasm separation,high-content screening,and immunofluorescence confocal focusing.Further studies have found that cGAS interacts with the nuclear transporters KPNA1 and CRM1 which provides evidence for the correctness of the predicted cGAS nuclear localization signal and nuclear export signal sequence.Next to cGAS in the physiological function of innate immune experiment,through transfection respectively two separate signal mutation plasmid into cells,the reuse VACV,ISD simulation of exogenous DNA stimulating cells by Western Blot and qPCR found missing out nucear signailan d the signaal of checl and ratify a cGAS expression cells to exogenous DNA(ISD.VACV)stimuli significantly lower innate immunity.cGAS subcellular localization according to its biology function plays an important role in innate immune.To sum up,it was identified in this paper that the nuclear localization signal sequence of cGAS was299KRKR302.and the nuclear export signal sequence of cGAS was 169LEKLKL174,and the mutation of the two signal sequences would decrease the ability of cGAS to activate innate imculity,which rnay indicate that the localization of cGAS in the cell would affect its activation of innate immunity.Determining the nuclear localization signal sequence and nuclear export signal sequence of cGAS can provide a more comprehensive understanding of the information related to cGAS,which can help to deepen the mechanism of cGAS activating innate immunity,and provide a more thorough understanding of innate immunity,so as to provide effective information for improving the innate immunity of the body.