A building block of two organelles

hen your gut tells you to run, it is wise to listen. Em-bryonic neural precursor cells do just that, according to De Bellard et al. (page 269), who identify the basis of an avoidance mechanism for migrating neural crest cells. Groups of embryonic neural precursors take separate paths on their way to forming the peripheral nervous system. Vagal cells, which emerge from the neck region, migrate long distances to enter the gut. Cells in the trunk originate closer to the gut yet never enter this region. The new results show that the gut is off limits because trunk cells sense Slit proteins, chemorepellents involved in axon guidance in flies and vertebrates. In chick embryos, Slit expression marked the entrance to the gut. The group injected Slit-expressing cells into embryos and found that trunk cells stopped in their tracks to avoid migrating through regions containing the chemorepellent. Vagal cells, in contrast, were unaffected by Slit proteins, as trunk but not vagal cells express the Slit receptors Robo1 and Robo2. Repulsion required contact between trunk cells and cells expressing surface-bound Slit. Slit administered in vitro is reused uniformily, so a simple repulsion effect is not obvious. But this form of Slit does cause trunk cells to migrate faster than vagal cells. In vivo, these two effects may combine to turn trunk cells away from the gut and speed their migration in the other direction. ᭿ W Migrating trunk cells (green) avoid Slit-expressing cells (red). n page 185, Kondylis and Rabouille find that a protein required for Golgi structure also organizes transitional ER (tER) sites, also known as ER exit sites. Although addressing tER assembly, the results might also influence models of Golgi formation. tER sites are enriched in COPII vesicles containing proteins destined for the Golgi. In fly S2 cells, tER sites are found adjacent to well-defined Golgi stacks. The authors have found that tER organization in S2 cells depends on dp115, of which mammalian homologues are necessary for vesicle transport and Golgi structure. In the absence of dp115, small tER sites that were no longer spatially associated with the Golgi were scattered O Kicking out antiviral proteins ike a bouncer at a club, the Epstein Barr virus (EBV) LMP1 protein removes a threatening presence by ejecting cellular proteins from the nucleus, according to Ohtani et al. on page 173. EBV infection leads to excessive cell proliferation that can cause disorders such …