Life-cycle and growth-phase-dependent regulation of the ubiquitin genes of Trypanosoma cruzi.

Background: Trypanosoma cruzi, the causative agent of Chagas disease, exhibits a complex life cycle that is accompanied by the stage-specific gene expression. At the molecular level, very little is known about gene regulation in trypanosomes. Complex gene organizations coupled with polycistronic transcription units make the analysis of regulated gene expression difficult in trypanosomes.

Ewing tumor fusion proteins block the differentiation of pluripotent marrow stromal cells.

The Ewing family of tumors are poorly differentiated pediatric solid tumors arising in bone and soft tissues from an unknown cell of origin. Ewing tumors are molecularly defined by in-frame genomic fusions that combine EWS with one of several ETS genes, most commonly FLI-1. We considered pluripotent marrow-derived stromal cells a likely candidate for the origin of Ewing tumors and assessed the effects of EWS/ETS proteins in this cell background.