Progenitor‐derived ribosomal RNA supports protein synthesis in Drosophila neurons

Abstract

Global mRNA translation may differ dramatically between progenitor cells and their differentiated progeny. One way cell type‐specific translation is established is through ribosome concentration. In addition to addressing unique metabolic needs, changes in ribosome concentration may influence cell fate. The mechanisms that determine ribosome abundance in progenitors versus differentiated progeny are not fully understood. Here, we investigated this process by focusing on ribosomal RNA (rRNA) synthesis in Drosophila neural progenitors and neurons. We found that rRNA synthesis is robust in neural progenitors but is limited in postmitotic neurons. Newly born neurons inherit rRNA from their progenitor parent and this inherited rRNA is sufficient for protein synthesis in neurons. Our findings support a model in which neuron‐specific translation programs are established by rRNA inheritance. Key Points This work links changes in ribosomal RNA (rRNA) synthesis, often assumed to be an invariant feature of cells, to neural differentiation. We describe a process of rRNA inheritance, where rRNA made in neural progenitors is passed to their progeny. We show that rRNA inheritance is sufficient for neural development and protein synthesis in neurons.