Fig. 1: Ribosome biogenesis builds its own factory.
From: RNA writes the nucleolus
Left: rRNA sequence elements contribute to the formation and spatial organization of nucleolar phases. Right: classical models posited that pre-existing nucleolar subcompartments guide ordered ribosome assembly. Newer evidence supports a reciprocal model: rRNA transcription, processing, and ribonucleoprotein assemblies establish nucleolar phase organization. “Cap” denotes the nucleolar caps formed when rRNA transcription is inhibited; “inside-out” nucleolus refers to the organization seen after disruption of U3-dependent early pre-rRNA processing.
