Using Single-Cell Techniques to Understand Noise in Gene Expression

Abstract

Signal transduction is the process by which an external signal is transmitted into a cell to induce a cellular response. Cells have evolved robust mechanisms to interpret and respond to these external signals as they modify gene expression by altering dynamics of transcription, translation, and post-translational modifications etc. These mechanisms are critical for development and maintaining homeostasis; nonetheless, isogenic cells still have fluctuations in RNA and protein abundance resulting in cellular heterogeneity (Lenstra et al., 2016). This heterogeneity may serve as a non-genetic mechanism to promote phenotypic diversity (Fraser & Kærn, 2009; Pujadas & Feinberg, 2012). A major source of cellular heterogeneity is regulatory noise resulting from molecular abundance (McAdams & Arkin, 1999; van Kampen, 2007), stage in cell cycle (Raser & O’Shea, 2005), and abundance of gene expression machinery (Huh & Paulsson, 2011). Single cell techniques have been utilized to track RNA and protein dynamics and localization to understand regulatory noise and elucidate previously unknown mechanisms in signaling transduction.