BPTF, the mammalian ortholog of Drosophila NURF301, is a large, multi-domain protein that is apparently exclusive to the mammalian NURF complex (Figure S1A) [12],[15],[25]. An initial characterization of Bptf showed it to be nuclear in the P19 embryonic carcinoma cell line and can exist in at least two electrophoretic variants, which we termed Bptf-H and Bptf-L (Figure S1B, Figure S1C). As previously reported, Bptf is highly expressed in testis, spleen, brain and to a lesser extent in kidney by Western blotting (Figure S1D). Interestingly Bptf is highly expressed during embryonic development, and expression substantially declines upon birth (Figure S1E). The high levels of Bptf expression in the mouse embryo suggest it may have essential functions during embryonic development.
