Transcriptome analysis of differentiating trypanosomes reveals the existence of multiple post-transcriptional regulons.
BACKGROUND
Trypanosome gene expression is regulated almost exclusively at the post-transcriptional level, with mRNA degradation playing a decisive role. When trypanosomes are transferred from the blood of a mammal to the midgut of a Tsetse fly, they transform to procyclic forms: gene expression is reprogrammed, changing the cell surface and switching the mode of energy metabolism. Within the blood, trypanosomes can pre-adapt for Tsetse transmission, becoming growth-arrested stumpy forms. We describe here the transitions in gene expression that occur during differentiation of in-vitro cultured bloodstream forms to procyclic forms.


RESULTS
Some mRNAs showed changes within 30 min of cis-aconitate addition, whereas others responded 12-24 hours later. For the first 12 h after addition of cis-aconitate, cells accumulated at the G1 phase of the cell cycle, and showed decreases in mRNAs required for proliferation, mimicking the changes seen in stumpy forms: many mRNAs needed for ribosomal and flagellar biogenesis showed striking co-regulation. Other mRNAs encoding components of signal transduction pathways and potential regulators were specifically induced only during differentiation. Messenger RNAs encoding proteins required for individual metabolic pathways were often co-regulated.


CONCLUSIONS
Trypanosome genes form post-transcriptional regulons in which mRNAs with functions in particular pathways, or encoding components of protein complexes, show almost identical patterns of regulation.
Zentrum für Molekulare Biologie der Universität Heidelberg, ZMBH-DKFZ Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany. r.queiroz@dkfz-heidelberg.de
Rafael
R
Queiroz
Corinna
C
Benz
Kurt
K
Fellenberg
Jörg D
JD
Hoheisel
Christine
C
Clayton
D016000:Cluster Analysis; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D020411:Oligonucleotide Array Sequence Analysis; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism; D016053:RNA, Protozoan / Q000378:metabolism; D018085:Regulon; D014345:Trypanosoma / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
D012333:RNA, Messenger; D016053:RNA, Protozoan