Lineage commitment and differentiation are likely to be coordinated by the combined effects of multiple transcription factors acting on numerous different target genes. The mechanisms by which lineage-restricted patterns of transcription factor expression are established are therefore of particular relevance to our understanding of the role of transcription factors both in normal development and in oncogenesis. Here, we report that the genes for the lineage-restricted transcription factors SCL, GATA-1 and GATA-2 are expressed in all multipotent, IL-3-dependent, haemopoietic progenitor cell lines tested. Moreover, a liquid differentiation assay has been used to demonstrate down regulation of SCL, GATA-1, GATA-2 and PU-1 during differentiation into non-expressing lineages. These data support the concept that multiple lineage-restricted transcription factors are expressed prior to lineage commitment.