The transcriptional factor GATA-4 negatively regulatesHsp70transcription inCrassostrea hongkongensis

摘要

To better explore the application potential of heat shock protein Hsp70s in diverse areas including biomonitoring, a further investigation of the details of the regulatory mechanism governing Hsp70 transcription is required. A transcriptional factorChGATA-4 that displayed affinity to theChHsp70promoter ofCrassostrea hongkongensiswas isolated and identified by DNA affinity purification as well as mass spectrometry analysis. TheChGATA-4cDNA is 2162 bp in length and the open reading frame encodes a polypeptide containing 482 amino acids with a conserved zinc finger domain. The over-expression ofChGATA-4significantly inhibited the expression ofChHsp70promoter in heterologous HEK293T cells. However, the depletion ofChGATA-4mRNA by RNAi technique resulted in significant increase ofChHsp70transcription in oyster hemocytes. The RT-PCR results demonstrated that the transcription of bothChHsp70andChGATA-4were induced by heat, Cd, or NP (Nonyl phenol) stress. This suggested a potential correlation betweenChHsp70andChGATA-4in the stress-mediated genetic regulatory cascade. This study demonstrated thatChGATA-4acts in a negative manner in controllingChHsp70transcription inC. hongkongensisand promotes to further understand the mechanisms leadingHsp70transcription.