Identification of apoptosis-related genes and transcription variations in response to microcystin-LR in zebrafish liver

There is growing evidence that the effects of microcystin-LR (MC-LR) are closely related to apoptosis. This study utilized microarray to identify the apoptosis-related genes induced by MC-LR in zebrafish liver. The messenger RNA abundance of some apoptosis-related genes was found to be increased, including five tumor necrosis factor (TNF)-related members (apoptosis regulatory protein siva, tumor necrosis factor-alpha (tnfa) TNF (ligand) superfamily member 10 (tnfsf10), TNF-inducible protein 6 (tnfaip6) and TNF receptor associated factor 2 binding protein (traf2bp)), three p53-related genes (tumor protein p53 inducible nuclear protein 1 (tp53inp1), p53-induced protein phosphatase 1 (ppm1d) and a novel apoptosis stimulating protein of p53 (aspp2)), bcl 2 family members (proapoptosis gene bax and antiapoptosis gene mcl 1), caspases (caspase y (caspy) and a PYD and CARD domain-containing protein (pycard)) and the transforming growth factor beta (TGF-beta) induced apoptosis protein 2 (taip2). Real-time polymerase chain reaction was used to study the kinetic transcriptional changes in seven apoptosis-related genes. Elevated transcription of p53, tp53inp1, mcl 1 and taip2 could only be detected at 6 h, increased transcription of the antagonist molecules, bcl 2 and bax could be detected at most time points and the significant change of caspy could be found at 48 h and 72 h after stimulation. Taken together, the results obtained in the present study clearly demonstrate that large amount of apoptosis-related genes are involved in the regulation of MC-LR-induced apoptosis