异源表达N-端融合eYFP标签的GAAPs增强拟南芥对ER胁迫敏感性

Golgi anti-apoptotic proteins (GAAPs) are highly conserved throughout eukaryotes and GAAP resembles BAX inhibitor-1 with inhibiting apoptosis triggered by various stresses in mammalian cells. Arabidopsis GAAPs have also been showed inhibited cell death induced by endoplasmic reticulum (ER) stress by reverse genetic assay. Except for the mutants, the transgenic plants expressing the gene fused with different tags are usually generated to study the function and its mechanism. But it should be caution whether the tag affect the protein function firstly. In the present study, we generated Arabidopsis plants overexpressing GAAP1 or GAAP4 tagged with eYFP at their N-terminal respectively. The sensitivity of eYFP-GAAP1/GAAP4 and gaap1 mutants to the ER-stress was tested. And the results showed that overexpressing eYFP-GAAP1/GAAP4 reduced the plant survival and enhanced cell death under ER stress, which was similar as gaap1 mutants. The quantitative real time PCR analysis showed that overexpressing eYFP-GAAP1 inhibited the activation of unfolded protein response (UPR) signaling pathway genes upon acute or prolonged ER stress. These data suggested that the eYFP tag at the N-terminal of GAAPs affected its function in the resistance of ER stress and anti-programmed cell death.