Functional analysis of CgPOU3F4L in the apoptosis regulation of Pacific oyster(Crassostrea gigas)exposed to high-temperature stress
In order to probe the role of CgPOU3F4L gene in the response to high-temperature stress in Pacific oys-ter(Crassostrea gigas),the composition and evolutionary features of POU family genes and the involvement of Cg-POU3F4L gene in the regulation of haemocyte apoptosis were investigated in 2 year old Pacific oyster exposed to water temperature of 28℃for 72 h.The results revealed that the Pacific oyster genome contained four POU family genes,namely CgPOU2F1,CgPOU3F4,CgPOU3F4L,and CgPOU4F3.The CgPOU3F4L possessed a unique a-mino acid sequence,the unclear functional differentiation characteristics of which are not yet clear.There were sig-nificantly higher mRNA expression levels of CgPOU3F4L in mantle,adductor muscle and haemocyte than that in hepatopancreas,as high 91.32,19.24 and 7.92 fold as that in hepatopancreas(P<0.05),as high 2.63 fold at 12 h,3.05 fold at 24 h and 3.62 fold at 36 h in the Pacific oyster exposed tp high-temperature stress as that in the control group(15℃)(P<0.05).POU transcription binding sites were found at 1 197-1 207 and 1 286-1 297 bp in the promoter region of apoptosis-related genes CgBcl-2 and CgCaspase3,respectively.RNAi method was applied to inhibit the expression of CgPOU3F4L,and the mRNA expression of CgBcl-2in CgPOU3F4L-RNAi group was shown to be increased significantly,which was 7.49-fold of that in the control group(P<0.001).Conversely,the mRNA expression level of CgCaspase3 was found to be decreased significantly,which was 0.57-fold of that in the control group(P<0.05).Additionally,the apoptosis rate of haemocytes(16.53%)was significantly lower than that in the control group(45.90%,P<0.001).It is approved that CgPOU3F4L gene regulates the apoptosis of haemo-cytes through the transcription regulation of CgBcl-2 and CgCaspase3 after high-temperature stress.These findings provide theoretical basis and reference for further understanding of the evolutionary characteristics of POU family and the mechanism of environmental stress response in oyster.
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维普
