Biochemical analysis of deacetylase activity of rice sirtuin OsSRT1, a class IV member in plants

The role of plant sirtuins is slowly unwinding. There are only reports of H3K9Ac deacetylation by OsSRT1. This belongs to class IV sirtuin family with a longer C-terminus. Here C-terminus is required for ligand binding and catalysis. OsSRT1 can deacetylate the lys residues at the N terminal tail of both H3 and H4. It can also target the non-histone target, OsPARP1 playing a role in DNA damage repair pathway. Changes in the extent of different histone deacetylation by OsSRT1 is also related with different abiotic stress conditions. NAM and ADP-ribose has negative effect on OsSRT1 deacetylation. Highlights OsSRT1 is capable of deacetylating various lysine residues of histone H3 and H4 as well as OsPARP1. The extra long C-terminus of OsSRT1 is required for its substrate binding and thus, its catalysis. On plant’s exposure to H 2 O 2 and Arsenic toxicity, there is a relationship between increased expression of OsSRT1 and increased deacetylation of H3 and H4.