Fig. 6: SIRT7 is O-GlcNAcylated at Ser136.

A Detection of the O-GlcNAcylation site(s) on SIRT7. SIRT7 was purified from HEK293T cells and analysed by LC-MS/MS analysis to identify the potential O-GlcNAcylation sites. The serine 136 O-GlcNAcylation site of SIRT7 was shown. B The O-GlcNAcylation levels of SIRT7 in PANC-1, MiaPaCa-2 and Bxpc-3 cells were detected. Endogenous SIRT7 was knocked down and then rescued by Flag-tagged SIRT7 WT, S134A, S136A, and S377A plasmids in these three cell lines. One representative experiment of n = 3 independent experiments is shown. C Serine 136 residue of SIRT7 is conserved in multiple species. D Western analysis of indicated cells treated with CHX (300 µg/ml) for 0, 1, 2, 4, 6, or 8 h. One representative experiment of n = 3 independent experiments is shown. E Co-IP assays of SIRT7 and REGγ were examined in indicated cells. One representative experiment of n = 3 independent experiments is shown. F The expression level of H3K18Ac in the indicated cells. One representative experiment of n = 3 independent experiments is shown. G The expression level of H3K18Ac in the indicated cells with or without OGT knockdown. One representative experiment of n = 3 independent experiments is shown. H Expression of SIRT7 target genes in SIRT7 WT and SIRT7 S136A PANC-1 cells, as determined by qPCR. One representative experiment of n = 3 independent experiments is shown. I ChIP-qPCR results showing H3K18Ac occupancy at the promoters of SIRT7 target genes in SIRT7 WT and SIRT7 S136A PANC-1 cells. One representative experiment of n = 3 independent experiments is shown. J ChIP-qPCR results showing SIRT7 occupancy at the promoters of SIRT7 target genes in SIRT7 WT and SIRT7 S136A PANC-1 cells. One representative experiment of n = 3 independent experiments is shown. The data are shown as the means ± SD. P values were calculated by two-tailed t-tests (*P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001; NS, no significance).