In Drosophila, the zinc-finger transcription factor Zelda is bound to regulatory regions of genes expressed by the zygote, and in zebrafish, the homeodomain protein Pou5f3 (a paralog of mammalian POU5F1 (OCT4) has an analogous role.
In Drosophila, the zinc-finger transcription factor Zelda is associated with regulatory regions that control gene expression in zygotes. Similarly, in zebrafish, the homeodomain protein Pou5f3 plays a similar role as its mammalian counterpart POU5F1 (OCT4).