Regulating Gene Expression in the Drosophila Germ Line

摘要

Germ cells are the ultimate stem cells because they have the potential to give rise to a new organism. Specified during earlyembryogenesis in most species, germ cells evade somatic differentiation by using mechanisms such as transcriptional silenc-ing and translational control (Seydoux and Braun 2006; Cinalli et al. 2008). To identify germ-line targets of translational reg-ulation and to understand their mechanism of regulation, we used publicly available databases to identify RNAs localized togerm plasm. Using a transgenic reporter assay, we find that these germ-line RNAs are both spatially and temporally regulatedduring both oogenesis and embryogenesis by their 3'-untranslated regions (3'UTRs) (Rangan et al. 2008). We find that manyRNAs that are spatially and temporally regulated in the early embryo are also translationally regulated during oogenesis.However, RNAs that are similarly regulated during oogenesis are no longer coregulated during embryogenesis, demonstrat-ing that cis-acting sequences within a single RNA are used differentially during the life cycle of the germ line. Our studyemphasizes a multifaceted role of translational regulation in germ cells. Many aspects of cellular behavior are shared betweengerm cells and other stem cells; thus, analysis of the translational regulatory networks controlling translation during the germ-line life cycle may reveal important general features of RNA regulation in stem cells.