When the tail wags the dog

Abstract

Flagella are whip-like structures that power the movement of certain cells. Analysis of a single-cell parasite, the African trypanosome, reveals that flagella are also essential for viability in this organism. There is little hope for a vaccine for African sleeping sickness, and most of the drugs currently used to treat it are old, not particularly effective and difficult to use in the conditions that prevail in sub-Saharan Africa, where the disease is endemic. So the discovery of a new class of molecule that might be targeted by drug intervention could be an important boost to the field. The sleeping sickness parasite Trypanosoma brucei is a protozoon equipped with a whip-like flagellum. RNA interference (RNAi) knock-down experiments show that a functioning flagellum is essential for Trypanosoma's survival in the bloodstream. That makes the flagellum a possible point of therapeutic attack, and proteomic analysis points to a number of trypanosome-specific flagellar proteins that could be targeted. On the cover, monstrous cells of bloodstream-form trypanosomes formed by a failure of cell division in cells with defective flagella.