PROGRAMMED CELL-DEATH IN PROCYCLIC TRYPANOSOMA-BRUCEI-RHODESIENSE IS ASSOCIATED WITH DIFFERENTIAL EXPRESSION OF MESSENGER-RNAS

Procyclic Trypanosoma brucei rhodesiense have a cell death mechanism w hich can be activated by an external signal, the lectin ConA, in vitro . ConA has been shown to cause profound changes in cellular morphology and induce fragmentation of nuclear DNA in T.b. rhodesiense which are characteristic of apoptosis, a form of programmed cell death (PCD) in other eukaryotic cells. RNA analysis of trypanosomes induced to under go PCD revealed that RNA remains intact up to 48 h into the process, a time when nuclear DNA fragmentation has already started. Using the ra ndomly amplified differentially expressed sequences polymerase chain r eaction method, ConA-induced cell death in T.b. rhodesiense is shown t o be associated with differential expression of mRNAs, including up re gulation of mRNAs late in the death process. The results demonstrate t hat trypanosomes actively participate in their own destruction through a PCD process and confirm that cell death in trypanosomes is associat ed with de novo gene expression.