However, FOG1 does not appear to require its major PXDLS CtBP-binding motif during erythropoiesis since mice carrying a FOG1 mutant with reduced CtBP binding develop normally, suggesting FOG1 recruits another repressor complex during erythropoiesis. The N-terminus of FOG1 appears to be particularly important for its function. During megakaryopoiesis, deletion mutants lacking residues 1�C144 could at least partially rescue erythroid but not megakaryocyte maturation, suggesting a lineage specific role for the N-terminal region. Subsequently, residues 1�C12 of FOG1 were shown to be able to mediate transcriptional 11-hydroxy-sugiol repression by GATA1, via recruitment of the nucleosome remodeling and deacetylation complex. Similarly, the Nterminal region of FOG2 represses GATA-4 activity, although the possibility remains open that other regions might contribute to repression. As part of an effort to understand the molecular mechanisms through which FOG1 regulates gene expression during hematopoietic development, we analyzed the amino acid sequence of murine FOG1. PRDM-family proteins are gene regulatory proteins that are found in metazoans, but not plants or fungi. Seventeen such proteins have been defined in primates, whereas only two are found in the sea squirt Ciona intestinalis, indicating a substantial expansion during vertebrate evolution. Their biological roles are still not well understood in many cases, but a number of family members appear to act in stem cells and in cellular differentiation. PRDM14 is important in stem cell biology and epigenetic reprogramming, PRDM3 is required for the integrity of heterochromatin and PRDM16 is essential for maintaining adipocyte identity. Not surprisingly therefore, dysregulation of PRDM Selamectin activity has been associated with several different types of cancer. All 17 human proteins contain an N-terminal PR domain and all but PRDM11 contain an array of between four and fifteen classical zinc fingers clustered in a range of different patterns. Although it is well accepted that the PR family of proteins acts to regulate gene expression, there is not yet a clear consensus on the biochemical mechanisms through which they achieve this outcome.