In many species, the reproductive cells of the germline can only form properly if certain mRNAs are prevented from translating into proteins until they have been transported to precise target locations in the egg and the appropriate developmental stage has been reached. In a study published in the January issue of Developmental Cell, members of the RIKEN Center for Developmental Biology (CDB) Laboratory for Germline Development (Akira Nakamura, Team Leader) report that, in the fruit fly Drosophila, this translational repression is achieved by a newly identified complex formed by three associating proteins.
RNA activity during Drosophila oogenesis involves a number of sequential processes. The Drosophila oocyte share cytoplasm with neighboring nurse cells via an incomplete cell membrane, allowing mRNAs and proteins from the nurse cells to be transported to the oocyte in the form of ribonucleoproteins. Following their export from the nurse cell nuclei, mRNAs are translationally repressed, or ‘masked,’ and transported to specified regions of the oocyte, where they establish fixed and precise localizations and regain their ability to undergo translation. In one example of this critically important regulation, the translation of the RNA for the maternal gene oskar, which has critical functions in embryonic patterning and the formation of germline cells, is repressed during its transport to the posterior pole of the oocyte. This transcript-specific repression is known to be mediated by the protein Bruno, which binds to the 3 UTR of oskar mRNA, but the underlying mechanisms have remained obscure.
In the Developmental Cell study, the Nakamura lab demonstrated that an ovarian protein, Cup, is another protein required to inhibit the premature translation of oskar mRNA, and that Cup achieves this by binding to a second protein, eIF4E, a 5 cap-binding general translation initiation factor. The binding with Cup prevents eIF4E from binding with a different partnering molecule, eIF4G, and thereby inhibits the initiation of translation. Findings that a mutant form of Cup lacking the sequence with which it binds eIF4E failed to repress oskar translation in vivo, that Cup interacts with Bruno in a yeast two-hybrid assay, and that the Cup-eIF4E complex associates with Bruno in an immunoprecipitation assay, suggesting that these three proteins form a complex that achieves translational repression by interactions with both the 3 and 5 ends of the oskar RNA. A similar model of protein interactions is observed in the translational repression of the cyclin-B1 RNA in the Xenopus African clawed frog, indicating that the paradigm of translational repression through the 5/3 interactions is conserved across species.
Doug Sipp | EurekAlert!
Cancer diagnosis: no more needles?
25.05.2018 | Christian-Albrechts-Universität zu Kiel
Less is more? Gene switch for healthy aging found
25.05.2018 | Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences