test the hypothesis that TRACK is involved in signal processes
in Trypanosoma brucei, the cellular content of TRACK was depleted
with RNAi. The following movie shows procyclic cells that have
been induced with tetracycline for 4 days, at which time western
blots show that TRACK is not detectable in the cells.
movie shows the formation of spicules at the posterior end of
the cell and cells that fail to complete the process of cytokinesis.
Cells continue to undergo multiple rounds of partial cell division.
Each partial division occurs non-synchronously, even though considerable
cytoplasm is shared between the "daughter cells". This
point becomes clear towards the end of the movie when cells with
odd-numbers of cytoplasmic extensions are seen. The fact that
cells are viable through multiple rounds of partial division suggests
that TRACK is not essential for other key processes in these cells.
Moreover, these are the first observations to indicate that cytokinesis,
once initiated is disjoint in trypanosomes. Protein(s) are required
for mid-stage progression that are not necessary for the initiation
stage of this process.