<p>Sequences of primers used in this study.</p>

Although METTL16 has been characterized in several model organisms, its function in <i>Drosophila</i> remains unknown. Here, we show that, unlike in mammals, <i>Drosophila Mettl16</i> mutants are viable but exhibit multiple developmental and behavioral defects.

Both male and female mutants are sterile, with severe gametogenesis defects. <i>Mettl16</i> mutant germ cells can pass the mitotic and meiotic stages, but are defective in spermatid elongation and individualization. Mettl16-GFP localizes predominantly to the nucleus, and its absence does not impair global protein synthesis in wing disc epithelial cells. MeRIP-Seq analysis indicates that Mettl16 loss affects m⁶A on only a small subset of transcripts, in contrast to the broad effect of Mettl3.