Single cell RNA-sequencing identifies a metabolic aspect of apoptosis in Rbf mutant

Majd M Ariss,Maxim V Frolov,Meg Critcher,Abul B M M K Islam,Maria Paula Zappia

doi:10.1038/s41467-018-07540-z

Majd M Ariss, Maxim V Frolov + Show 3 more

Open Access

https://doi.org/10.1038/s41467-018-07540-z

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Abstract

The function of Retinoblastoma tumor suppressor (pRB) is greatly influenced by the cellular context, therefore the consequences of pRB inactivation are cell-type-specific. Here we employ single cell RNA-sequencing (scRNA-seq) to profile the impact of an Rbf mutation during Drosophila eye development. First, we build a catalogue of 11,500 wild type eye disc cells containing major known cell types. We find a transcriptional switch occurring in differentiating photoreceptors at the time of axonogenesis. Next, we map a cell landscape of Rbf mutant and identify a mutant-specific cell population that shows intracellular acidification due to increase in glycolytic activity. Genetic experiments demonstrate that such metabolic changes, restricted to this unique Rbf mutant population, sensitize cells to apoptosis and define the pattern of cell death in Rbf mutant eye disc. Thus, these results illustrate how scRNA-seq can be applied to dissect mutant phenotypes.

Highlights

The function of Retinoblastoma tumor suppressor is greatly influenced by the cellular context, the consequences of pRB inactivation are cell-type-specific
Despite hid being upregulated throughout almost the entire Rbf mutant eye disc, apoptosis is restricted to cells anterior to the morphogenetic furrow that show a transient reduction in epidermal growth factor receptor (EGFR) signaling[4]
We found that its expression is restricted to photoreceptors and absent in interommatidial cells (Fig. 3a, c). cpo is strongly expressed in wrapping glial cells of WG+SPG (Fig. 3d) and this was validated with a cpo-lacZ reporter line (Fig. 3b, d)

Summary

Introduction

The function of Retinoblastoma tumor suppressor (pRB) is greatly influenced by the cellular context, the consequences of pRB inactivation are cell-type-specific. Genetic experiments demonstrate that such metabolic changes, restricted to this unique Rbf mutant population, sensitize cells to apoptosis and define the pattern of cell death in Rbf mutant eye disc. These results illustrate how scRNA-seq can be applied to dissect mutant phenotypes. The Rbf mutant eye disc represents an ideal setting to apply scRNA-seq methodology and identify a precise cellular context that makes Rbf mutant cells sensitive to apoptosis. We find a transcriptional switch during photoreceptor differentiation We utilize this resource to examine the Rbf mutant phenotype and identify a specific population of cells with increased glycolysis that makes them sensitive to E2F-dependent apoptosis. Our results illustrate the applicability of scRNA-seq to profile mutant phenotypes

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Conclusion