Hippo pathway and Bonus control developmental cell fate decisions in the Drosophila eye

The Hippo pathway controls organ growth, however its role in cell fate determination and the underlying mechanism is not well understood. Here, we uncover the function of the Hippo pathway in developmental cell fate decisions in the Drosophila eye, exerted through the interaction of Yorkie (Yki) with a transcriptional regulator Bonus (Bon). Activation of either Bon or Yki is sufficient to promote epidermal fate at the expense of eye fate through the recruitment of multiple transcriptional and post-transcriptional regulators. Transcriptome analysis reveals that Bon and Yki jointly upregulate epidermal differentiation genes and downregulate Notch target genes that modulate the eye-to-epidermal fate switch. The Hippo pathway and Bon also control the early eye-antennal specification, with activated Yki and Bon suppressing eye fate and promoting antennal fate. Our work has revealed that the Hippo pathway and Bon control cell fate decisions during Drosophila eye development at multiple levels. ### Competing Interest Statement The authors have declared no competing interest.