Single-cell RNA sequencing reveals dynamic paracrine control of cellular variation. In this study, researchers analyzed over 1,700 single-cell RNA-Seq libraries from mouse bone marrow-derived dendritic cells (DCs) under various experimental conditions. They found significant variation in gene expression between identically stimulated DCs, with distinct gene modules exhibiting different temporal heterogeneity profiles. A "core" antiviral gene module was expressed early by a few "precocious" cells but later activated in all cells. By using microfluidic chambers to isolate cells and analyzing DCs from knockout mice, they demonstrated that this response is coordinated via interferon-mediated paracrine signaling. Surprisingly, preventing cell-to-cell communication also reduced variability in the expression of an early-induced "peaked" inflammatory module, suggesting that paracrine signaling represses part of the inflammatory program. The study highlights the importance of cell-to-cell communication in controlling cellular heterogeneity and reveals general strategies that multicellular populations use to establish complex dynamic responses. Single-cell RNA-Seq data showed that gene expression variation can be divided into digital and analogue variation. Digital variation reflects the percentage of cells detectably expressing a transcript, while analogue variation represents expression level variation among detectably expressing cells. The study also found that chromatin levels correlate with digital variation, and that changes in the expression of bimodally expressed genes can reflect shifts in the amount of transcript made by expressing cells or the proportion of expressing cells. The study further showed that intercellular communication is crucial for coordinating the "core" antiviral response and dampening the "peaked" inflammatory program. Paracrine interferon signaling affects the digital variation of "peaked" inflammatory genes, and the study identified that a secondary, IFN-β-dependent signal is involved in this process. The findings suggest that cell-to-cell communication plays a critical role in regulating immune responses, and that different gene modules can be affected by intercellular signaling in opposing ways. The study also highlights the importance of understanding the mechanisms underlying immune responses, as well as the potential implications for diseases such as autoimmune disorders.Single-cell RNA sequencing reveals dynamic paracrine control of cellular variation. In this study, researchers analyzed over 1,700 single-cell RNA-Seq libraries from mouse bone marrow-derived dendritic cells (DCs) under various experimental conditions. They found significant variation in gene expression between identically stimulated DCs, with distinct gene modules exhibiting different temporal heterogeneity profiles. A "core" antiviral gene module was expressed early by a few "precocious" cells but later activated in all cells. By using microfluidic chambers to isolate cells and analyzing DCs from knockout mice, they demonstrated that this response is coordinated via interferon-mediated paracrine signaling. Surprisingly, preventing cell-to-cell communication also reduced variability in the expression of an early-induced "peaked" inflammatory module, suggesting that paracrine signaling represses part of the inflammatory program. The study highlights the importance of cell-to-cell communication in controlling cellular heterogeneity and reveals general strategies that multicellular populations use to establish complex dynamic responses. Single-cell RNA-Seq data showed that gene expression variation can be divided into digital and analogue variation. Digital variation reflects the percentage of cells detectably expressing a transcript, while analogue variation represents expression level variation among detectably expressing cells. The study also found that chromatin levels correlate with digital variation, and that changes in the expression of bimodally expressed genes can reflect shifts in the amount of transcript made by expressing cells or the proportion of expressing cells. The study further showed that intercellular communication is crucial for coordinating the "core" antiviral response and dampening the "peaked" inflammatory program. Paracrine interferon signaling affects the digital variation of "peaked" inflammatory genes, and the study identified that a secondary, IFN-β-dependent signal is involved in this process. The findings suggest that cell-to-cell communication plays a critical role in regulating immune responses, and that different gene modules can be affected by intercellular signaling in opposing ways. The study also highlights the importance of understanding the mechanisms underlying immune responses, as well as the potential implications for diseases such as autoimmune disorders.