The Study Of Retinoic Acid Regulating Tyrosinase Expression In Crassostrea Gigas

Some progress has been made in selective breeding of black Pacific oysters(crassostrea gigas),but the mechanism of melanin production remains unclear.As an important active substance in organism,retinoic acid not only regulates embryonic development and differentiation at early stage,but also has important influence on body color change during development.In a previous study of Pacific oysters,no evidence has been found that the variation of tyrosinase gene coding region is related to shell color formation,however,it has been found that the transcription levels of retinal dehydrogenase and tyrosinase genes in the mantle of black-shell oysters were significantly higher than those in white-shell oysters.On the basis of preliminary work and research results,we propose hypotheses: when the expression of retinal dehydrogenase was up-regulated,more retinoic acid was produced.It will bind to the retinoic acid receptor to form the retinoic acid-retinoic acid receptor complex,which will combined with the retinoic acid reaction elements in the tyrosinase gene regulatory region,the expression of tyrosinase gene was up-regulated,and then produce more melanin.The results are summarized as follows: 1 Physiological study of retinic acid exposure in crassostrea gigasLive crassostrea gigas was used as experimental material,from the perspective of physiological and biochemical experiments,injecting exogenous retinoic acid on body surface exposure,Retinoic acid solvent was used as the control variable simultaneously,Mantle tissue and crust were taken as samples after exposure,optical analysis instruments were used to analyze the apparent pigment differences,The results showed that the injection exposure of retinoic acid will deepen the color of the inner shell of crassostrea gigas,and there is a significant difference in the relative content of melanin in the mantle,which can be analyzed as the high retinoic acid content in the internal environment may promote the increase of melanin content.The reason is that the environment with high retinic acid content may promote the increase of melanin content.The differences in the content of melanin-related tyrosinase were detected by using the enzyme-linked immunoassay kit for mollusks.The results showed that the content of tyrosinase in the retinoic acid exposed group was significantly increased,indicating that retinoic acid could affect the deposition of pigment by affecting the content of tyrosinase in the body.2 Experimental study on retinic acid exposure of crassostrea gigasThe coat samples of crassostrea gigas exposed to retinic acid were used as experimental materials,from the perspective of molecular biology,real-time fluorescence quantitative PCR was used to detect the relative expression of tyrosinase gene in two groups of exposed samples and the effect of retinal dehydrogenase gene expression related to retinoic acid.The results showed that the expression of tyrosinase gene in retinic acid exposure group was up-regulated,and the difference was significant.And further test showed that the relative expression difference of upstream retinaldehyde dehydrogenase gene was downregulated,and the T test result was P=0.052.Therefore,it is speculated that retinoic acid can not only affect the expression of tyrosinase gene in vivo and then affect the deposition of pigment,but also may affect the expression of retinoic acid dehydrogenase gene due to the presence of high concentration of retinoic acid in vivo.3 Study on the relationship between retinaldehyde dehydrogenase gene and tyrosinase gene in crassostrea gigasLive crassostrea gigas was used as experimental material,The expression interference of retinal dehydrogenase gene related to retinoic acid was conducted by using RNAi technology in mollusks,and then the expression of tyrosinase gene was detected to analyze the relationship between each gene and retinoic acid.Based on the above experiments,the regulatory effects of retinoic acid and tyrosinase genes were analyzed and summarized,and the mechanism of retinoic acid on Pacific oysters was speculated,the molecular mechanism of retinal dehydrogenase affecting melanin production in Pacific oysters by regulating tyrosinase gene expression was summarized.Based on the above experiments,the regulatory effects of retinoic acid and tyrosinase genes were analyzed and summarized,and the mechanism of retinoic acid on physiological activities of Pacific oysters was speculated,so as to summarize the molecular mechanism of retinal dehydrogenase affecting the production of melanin in Pacific oysters by regulating the expression of tyrosinase gene.The results showed that abnormal expression of retinal dehydrogenase gene can down-regulate the expression of Pacific oysters tyrosinase gene,which may be related to the interference of its own expression in regulating the production of retinoic acid,thus acting on the relevant tyrosinase gene.It may eventually affect the deposition of pigment in the body,and extend the duration of action may also affect the body color.This study proved that retinoic acid could affect the deposition of melanin by regulating the expression of the tyrosinase gene of Pacific oysters.The abnormal expression of the retinal dehydrogenase gene of Pacific oysters could not only affect the catalytic generation of retinoic acid by retinal,but also affect the expression of the tyrosinase gene of Pacific oysters,thus affecting the deposition of melanin.It can be inferred that retinoic acid plays an important positive regulatory role in the pigmentation of Pacific oysters.