Fig. 7. Model for the establishment of a euchromatic chromatin state by ectopic H3S10 phosphorylation. (A) lacO repeats (in red) inserted into a polytene band region with condensed chromatin in the absence of LacI-JIL-1 expression. The region has normal band-interband morphology. (B) When LacI-JIL-1 is expressed, the extended region of lacO repeats recruits high levels of LacI-JIL-1, which in turn hyperphosphorylates histone H3S10 at the target site as well as at adjacent chromatin regions. The ectopic phosphorylation of histone H3S10 subsequently induces the release of condensing factors and/or recruits chromatin remodeling factors, resulting in a euchromatic chromatin state at and near the insertion site.