| CD36(Cluster of differentiation36) is a transmembrane glycoprotein with singlepolypeptide, belongs to class B scavenger receptor family. It is expressed in varioustissues and cells in mammals，and it shows diverse expression patterns in differenttissues and cells which could explain its multi-function. It reported that CD36has anequally range of ligands, according to its ligand diversity, thus it participates invarious physiological and pathological processes, such as uptake of modified lipid,the perception of high fat diet, adhesion, inflammatory response, angiogenesis,atherosclerosis, diabetes, and cardiomyopathy. Moreover, it may play an importantrole in internalization and signaling. At present, the study of CD36is mainly focus onmammals, but its role in fish is still unknown. In this study, zebrafish was chosen tostudy the tissue distribution and expression pattern in embryonic developmental stageof CD36gene and its major functions. In addition, catfish was chosen to detect thelocalization of CD36in taste buds. This is the first study on CD36gene in fish, whichwould lay the foundation for a comprehensive exploration of its functions in fish.The tissue distribution of zebrafish CD36was detected by semi-quantitativeRT-PCR. It is found that zebrafish CD36gene mRNA has a wide distribution in alldetected tissues. However, CD36is expressed strongly in intestines, liver, spleen, gillsand brain, whereas expressed at a lower intensity in backbone, kidney and swimbladder. The expression of zebrafish CD36protein was detected byimmunohistochemical. It is indicated that CD36protein exist in the lip of zebrafish,which we speculated that it might be located in taste buds (need further verification).The developmental expression of zebrafish CD36were detected by quantitivereal-time PCR. CD36is expressed diversely in different stage of embryos, and it isexpressed maternally at high levels in the early stages, then reduced sequentially, but began to rise at hatching stage. It is possible that CD36play an important role in thedevelopment of embryos. Whole-mount in situ hybridization on embryos showed thesame trend to quantitive real-time PCR analysis, that CD36is widely expression inthe early stages of embryos; it is concentrated in head and abdomen aftersegmentation stage; in about7days juvenile fish, the signal is weaken in the wholebody but still concentrated in head and abdomen. Sectioning of the juvenile fishwhich has been hybridized, we found that the signal of CD36mainly distributed intissues that contain taste buds and digestion tissue. It is indicated that CD36mightplay a significant role in early embryogenesis.In order to uncover whether CD36participate in fish immune, LPS, LTA werechosen to stimulate adult zebrafish, then detected the response of CD36was detectedby quantitive real-time PCR. It was found that LPS and LTA induced CD36up-regulated in liver, thus we speculated that it might participate in immunizationresponse. We also detected CD36mRNA expression of juveniles in different nutritionfeeding conditions by quantitive real-time PCR. It is showed that CD36mRNAexpreesion was decreased with refeed high fat diet after fasted14days; butup-regulated with fasted12hours after high fat diet feeding14days. Moreover,linoleic acid could induced CD36mRNA expression in taste tissues of zebrafish. It issuggested that CD36may participate in the perception of lipids,but further research isrequired. According to the evidences in zebrafish, we chose catfish which hasadvanced taste buds for the further research. Immunofluorescent histochemical ofcatfish showed that5-HT, the marker of taste buds, expressed in taste budsspecifically. Moreover, we also studied the localization of CD36in taste buds.Together these results, it is may lay the foundation for the research of CD36in theperception of lipids in fish. |
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