Molecular states underlying neuronal cell type development and plasticity in the postnatal whisker cortex
Fig 3
L2/3 pyramidal cell type composition and gene expression are selectively regulated during development.
(A) Schematic for transferring P22 cell type labels (reference data) to P12 cells to facilitate cell type-level comparisons. (B) Within glutamatergic neurons (~80% of all neurons), all cell types except for L2/3_A and L2/3_B have approximately the same relative frequency between P12 and P22. Pearson correlation coefficient between the relative frequencies is indicated on top (S1 Data). (C) Scatter plot of PC1 vs. PC2 for L2/3 neurons at P12 (top row) and P22 (bottom row). Within each row, the leftmost panel highlights cells colored by their type-identity (L2/3_A, L2/3_B, and L2/3_C). In the remaining three panels within each row, cells are colored based on their aggregate expression levels of markers for each type (see Materials and methods). Between P12 and P22, L2/3_A markers decrease in expression and increase in specificity, while L2/3_B markers increase in expression during development, driving cell type identity maturation (S1 Data). (D) Representative FISH images showing labeling of cell type markers Cdh13, Trpc6, and Chrm2 at P12 and P22 within wS1 L2/3. Arrowheads indicate putative Cdh13-expressing interneurons (See S5A Fig). (E) Summary plots based on overlay of all images of L2/3 visualizing expression of Cdh13, Trpc6, and Chrm2 at P12 and P22. Circles represent individual excitatory cells within L2/3, colored based on their expression of one or more marker genes (color code as in panel E). To the right of each summary plot is the kernel density estimate for each type along the pial-ventricular axis. Cdh13+ cells dominate in upper L2/3 at P12, whereas Trpc6+ cells are more abundant at P22. N = 10–12 slices from 3 mice per time point. (F) Quantification of the fraction of excitatory (Slc17a7+) L2/3 cells expressing one or more markers Cdh13, Trpc6, and Chrm2 at P12 and P22. N = 10–12 slices from 3 mice per time point (S1 Data).