Transcription of early somatic cells during differentiation.
(A) Illustration of early oogenesis featuring annotated somatic cell types of interest (colored according to identity in panel C) and germline (gray). (B) Fig 1B UMAP (gray) highlighting the 1,837-cell subset of early somatic cell clusters 3–7 (black) reclustered in Monocle for pseudotime analysis. (C) Trajectory tSNE of subset cells ordered along pseudotime. (C') Pseudotime-ordered heat map from trajectory in panel C with select genes (transcriptional regulators: GO:0140110 or PC00218, and MAPK signaling pathway: KEGG:04013) selected from expression in a minimum of 20 cells, q < 0.05. (D) Trajectory tSNE of the 479-cell subset (excluding mitotic follicle cells). (D') Pseudotime-ordered heatmap from trajectory in panel D. Minimum expression = 20 cells, q < 1e−5. (E) Enriched Biological Process terms for somatic cells in germarium cluster and mitotic follicle, polar, and stalk cell branches. Adjusted p-values (Padj) are provided for each term. (F) Expression plots of validated genes arranged along pseudotime (from trajectory in panel C) comparing the mitotic follicle cell (solid line) and polar/stalk cell (dotted line) branches. Data are available through GEO database (GSE146040). (G) Experimental validation of select genes (green) using GFP-tagged proteins under endogenous control. All images are z-projections. Ovarioles are outlined in gray. Germline outlined in top left image. Some expression is also observed in other cell types and marked with an asterisk (epithelial sheath cells in bottom right image and germline cells in top left image). Scale bar = 20 μm. GO, gene ontology; KEGG, Kyoto Encyclopedia of Genes and Genomes; MAPK, Mitogen-Activated Protein Kinase; PC, principal component; tSNE, t-Distributed Stochastic Neighbor Embedding; UMAP, Uniform Manifold Approximation Projection.
