Figure 3. Transcription Factor Expression in ORNs.

(A) Schematic showing three kinds of transcription factors (TFs) that regulate olfactory receptor expression and wiring specificity.

(B) Scatter plots showing number of cells in which a gene can be detected versus the mean expression level of the gene in all cells. TFs are highlighted. A positive cell is defined as the cell expressing a gene at the level of Log₂(CPM+1) ≥3. CPM, counts per million. This analysis shows that TFs have a wide range of expression patterns, from a few cells or all cells, and that the overall TF expression level is comparable with other types of genes.

(C) Distributions of the number of TFs detected per ORN at the level of Log₂(CPM+1) ≥ 3.

(D) Sparsity and expression level of the TFs among ORN transcriptomic clusters. Each dot is one TF. A positive cluster is defined as more than 30% cells in the cluster expressing the TF at the level of Log₂(CPM+1) ≥ 3. Highlighted in red are three example genes, unpg, eyg, and acj6, with high mean expression levels but different sparsity.

(E) tSNE plots showing expression of unpg, eyg, and acj6. Expression levels are indicated by the color bar. In the acj6 tSNE plot, two clusters corresponding to DL4 and DM6 are indicated.

Feature maps like those shown in (E) can be produced for any of the transcription factors listed in (D) using transcriptomic data we have deposited in Github.