Comparative expression analysis of the antagonistic transcription factors EVI1 and MDS1-EVI1 in murine tissues and during in vitro hematopoietic differentiation.

An alternative form of the transcription factor EVI1, MDS1-EVI1, which previously had been believed to exist only in the context of leukemic fusion mRNAs, has recently been shown to be expressed also in normal human tissues. Moreover, it acts as an antagonist of EVI1, activating transcription of reporter constructs repressed by EVI1. We cloned the murine homolog of MDS1-EVI1 as well as mMds1 and show localization of mMds1 close to mEvi1 on chromosome 3. Using RT-PCR, we demonstrate widespread expression of both Evi1 forms in the adult mouse, as well as their upregulation during in vitro hematopoietic differentiation. Our data underscore the biological importance of both EVI1 and MDS1-EVI1 and provide the basis for further studies of their function in the mouse model system. Copyright 1998 Academic Press.