7.0 years ago by
Athens, GA, USA
As Daler suggests, current evidence for BEAF32 at least is that it is Drosophila-specific. See "The phylogenetic distribution of non-CTCF insulator proteins is limited to insects and reveals that BEAF-32 is Drosophila lineage specific.": http://www.ncbi.nlm.nih.gov/pubmed/20024537
From an analysis of Su(Hw), Zw5, CTCF, GAF, Mod(mdg4), and BEAF-32: "all insulator proteins, with the exception of CTCF, which has also been identified in vertebrates and worms, have been exclusively described in Drosophila melanogaster. In this work, we have performed database searches utilizing each D. melanogaster insulator protein as a query to find orthologs in other organisms, revealing that except for CTCF all known insulator proteins are restricted to insects. In particular, the boundary element-associated factor of 32 kDa (BEAF-32), which binds to thousands of sites throughout the genome, was only found in the Drosophila lineage."