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Biology subjects

Delventhal, K.

Publications and source records attributed to Delventhal, K..

2 recordsLinked to original sources

A new genetically tractable non-vertebrate system to study complete camera-type eye regeneration

Camera-type eyes are complex sensory organs susceptible to irreversible damage. Their repair is difficult to study due to the paucity of camera-type eye regeneration models. Identifying a genetically tractable organism with the ability to fully regenerate complete camera-type eyes would help overcome this difficulty. Here, we introduce the apple snail Pomacea canaliculata, capable of full regeneration of camera-type eyes even after complete resection. We defined anatomical components of P. canaliculata eyes and genes expressed during crucial steps of their regeneration. By exploiting the unique features of this organism, we successfully established the first stable mutant lines in apple snails. Our studies revealed that, akin to humans, pax6 is indispensable for eye development in apple snails, establishing this as a research organism to unravel the mechanisms of camera-type eye regeneration. This work expands our understanding of complex sensory organ regeneration and offers new ways to explore this process.

developmental biology↗

rRNA transcription is integral to liquid-liquid phase separation and maintenance of nucleolar structure

Beginning with transcription of ribosomal RNA (rRNA) by RNA Polymerase (Pol) I in the nucleolus, ribosome biogenesis is intimately tied to cell growth and proliferation. Perturbation of ribosome biogenesis has been previously shown to affect nucleolar structure, yet the underlying mechanism is unknown. We generated loss-of-function mouse mutants of Pol I subunits, Polr1a, Polr1b, Polr1c and Polr1d, thereby genetically inhibiting rRNA transcription and ribosome biogenesis. Pol I mutant embryos are preimplantation lethal and have fewer nucleoli. Using hiPSCs triple labeled for the three nucleolar compartments, we observe two phenotypes upon Pol I inhibition: a single condensed nucleolus, and fragmented nucleoli. We find that when rRNA transcription is inhibited, the viscosity of the granular compartment of the nucleolus is increased disrupting its liquid-liquid phase separation properties, which results in a condensed nucleolus. Taken together, our data suggests that Pol I function and rRNA transcription are required for maintaining nucleolar structure and integrity.

developmental biology↗