2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/117016Stochastic gene expression has been implicated in a variety of cellular processes, including cell differentiation and disease. In this issue of Cell, Weinberger et al. (2005) take an integrated computational-experimental approach to study the Tat transactivation feedback loop in HIV-1 and show that fluctuations in a key regulator, Tat, can result in a phenotypic bifurcation. This phenomenon is observed in an isogenic population where individual cells display two distinct expression states corresponding to latent and productive infection by HIV-1. These findings demonstrate the importance of stochastic gene expression in molecular "decision-making."Supplemental data available as q-bio.MN/0608003Molecular NetworksSoft Condensed MatterBiological PhysicsCell Behaviortext