Nuclear bodies: RNA‐rich powerhouses of the cell (471.3)

Abstract

A common organizational feature of cell nuclei is the presence of RNA‐rich subcompartments called “bodies”. These bodies are not enclosed by lipid bilayers, yet they provide a microenvironment where specific sets of proteins and RNA are concentrated. My lab has focused on the Cajal body (CB) and more recently the histone locus body (HLB) to investigate the structure and function of nuclear bodies with relevance to at least two different functions in RNA processing: the CB is the site of assembly of the spliceosomal snRNPs, required in pre‐mRNA splicing, and the HLB is the site of transcription and 3’ end formation of histone mRNA. I will discuss the similarities and differences in molecular composition, dynamics and function among CBs and HLBs. The roles of CBs and HLBs in the context of early zebrafish embryogenesis will be explored, focusing on the periods before, during and after zygotic genome activation. The emerging model is that nuclear bodies facilitate efficient assembly of macromolecular complexes through networks of low affinity interactions among binding partners. The active role of RNA in nuclear morphology as well as rules governing the trafficking of RNA to and from nuclear bodies will be highlighted.