Two novel proteins with opposing m6A writing functions interact with HAKAI [meRIP-seq]

Using in vivo interaction proteomics, two HAKAI-interacting zinc finger proteins, HIZ1 and HIZ2, were discovered as novel components of the Arabidopsis m6A writer complex. HAKAI is required for the interaction between HIZ1 and MTA. Whilst HIZ1 knockout plants have normal levels of m6A, plants in which it is overexpressed show reduced methylation. In addition, HIZ1 was found to be involved in root hair development upon auxin transport inhibition in a HAKAI-dependent manner. Mutant plants lacking HIZ2 are viable but have an 85% reduction in m6A abundance and show severe developmental defects. Our findings suggest that HIZ1 appears to be a HAKAI-dependent negative regulator of m6A deposition and HIZ2 is a novel and essential member of the Arabidopsis m6A writer complex. MeRIPSeq analysis of Arabidopsis m6A writer complex member mutants including HAKAI, Virilizer and FIP37. We used 3 replicates of each mutants and wt. Each experiment had an input and an IP sample