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bioRxiv · 10.1101/2021.10.27.466115

The Ribb-osome: Ribbon boosts ribosomal protein gene expression to coordinate organ form and function

Loganathan, R.·Levings, D. C.·Kim, J. H.·Wells, M. B.·Chiu, H.·Wu, Y.·Slattery, M.·Andrew, D. J.
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Abstract

Cell growth is well defined for the late (post-embryonic) stages of development, but evidence for early (embryonic) cell growth during post-mitotic morphogenesis is quite limited. Here, we identify early cell growth as a key characteristic of tubulogenesis in the Drosophila embryonic salivary gland (SG). A BTB/POZ domain nuclear factor, Ribbon (Rib), mediates this early cell growth. Rib binds the transcription start site of nearly every SG-expressed ribosomal protein gene (RPG) and is required for full expression of all RPGs tested. Rib binding to RPG promoters in vitro is weak and not sequence-specific, suggesting that specificity is achieved through co-factor interactions. Consistent with this hypothesis, we demonstrate Ribs ability to physically interact with each of the three known contributors to RPG transcription. Surprisingly, Rib-dependent early cell growth in another tubular organ--the embryonic trachea--is not mediated by direct RPG transcription. These findings support a model of early cell growth sustained by transcriptional regulatory networks customized for organ form and function.

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Loganathan, R., Levings, D. C., Kim, J. H., Wells, M. B., Chiu, H., Wu, Y., Slattery, M., Andrew, D. J.. 2021-10-28. The Ribb-osome: Ribbon boosts ribosomal protein gene expression to coordinate organ form and function. https://doi.org/10.1101/2021.10.27.466115

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