Posttransscriptonal regulation of the nanos mRNA in Drosophila melanogaster

• Applicant: Professor Dr. Elmar Wahle
• Subject Area: Cell Biology
• Term: from 2007 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 33442413

The nanos mRNA encodes a key determinant for development of the posterior end of the Drosophila embryo. Nanos is under strict posttranscriptional control: Non-localized nanos RNA is deadenylated and translationally repressed. Both deadenylation and repression are governed by binding sites for the protein Smaug (Smaug response elements, SREs) in the 3' UTR. Nanos RNA localized at the posterior pole is activated by Oskar. We have developed a cell-free system that reproduces SRE-dependent translational repression and deadenylation as well as activation by Oskar. We have found that a repressor complex assembled in an SRE-dependent manner prevents the initiation of translation at the earliest detectable stage. Assembly of the repressor complex is slow and requires ATP, and the complex is kinetically unusually stable. The repressor complex contains Smaug and the CCR4-NOT complex, a known deadenylase. It also contains several proteins known to be involved in other cases of translational repression, in particular the RNA-dependent ATPase Me31B. We now want to analyze the composition of the SRE-dependent repressor complex, the mechanism by which it causes translational repression and deadenylation and the roles of individual components of the complex.

• DFG Programme: Research Units
• Subproject of: FOR 855: Cytoplasmic Regulation of Gene Expression