Developmental regulation of gene expression in the absence of transcriptional control: the case of kinetoplastids.

Kinetoplastids, including the human pathogens Trypanosoma brucei, Trypanosoma cruzi and Leishmania, are the only known organisms that do not regulate the transcription of protein coding genes transcribed by RNA polymerase II. Yet, profound changes in gene expression are induced by many different external stimuli and stresses, the extreme example are cascades of changes in gene expression initiated by differentiation triggers that ultimately and irreversibly result in the massive morphological and metabolic changes observed during life-cycle progression. This review explores how kinetoplastids change gene expression by looking at life-cycle stage specific changes in chromatin, mRNA processing, mRNA stability, mRNA translation, protein stability and protein modifications.