Role of Hakai in m6A modification pathway in Drosophila

Abstract

AbstractN6-methyladenosine (m6A), the most abundant internal modification in eukaryotic mRNA, is installed by a multi-component writer complex; however, the exact roles of each component remain poorly understood. Here we show that a potential E3 ubiquitin ligase Hakai colocalizes and interacts with other m6A writer components, andHakaimutants exhibit typical m6A pathway defects inDrosophila, such as lowered m6A levels in mRNA, aberrantSxlalternative splicing, wing and behavior defects. Hakai, Vir, Fl(2)d and Flacc form a stable complex, and disruption of either Hakai, Vir or Fl(2)d led to the degradation of the other three components. Furthermore, MeRIP-seq indicates that the effective m6A modification is mostly distributed in 5’ UTRs inDrosophila, in contrast to the mammalian system. Interestingly, we demonstrate that m6A modification is deposited onto theSxlmRNA in a sex-specific fashion, which depends on the m6A writer. Together, our work not only advances the understanding of mechanism and regulation of the m6A writer complex, but also provides insights into how Sxl cooperate with the m6A pathway to control its own splicing.