TY - JOUR T1 - The <em>Drosophila</em> Fab-7 boundary element modulates <em>Abd-B</em> gene activity in the genital disc by guiding an inversion of collinear chromatin organization and alternative promoter use JF - bioRxiv DO - 10.1101/2022.04.26.489596 SP - 2022.04.26.489596 AU - Laura Moniot-Perron AU - Benoit Moindrot AU - Line Manceau AU - Joanne Edouard AU - Yan Jaszczyszyn AU - Pascale Gilardi-Hebenstreit AU - Céline Hernandez AU - Sébastien Bloyer AU - Daan Noordermeer Y1 - 2022/01/01 UR - http://biorxiv.org/content/early/2022/04/26/2022.04.26.489596.abstract N2 - Hox genes encode transcription factors that specify segmental identities along the Antero-Posterior body axis. These genes are organized in clusters, where their order corresponds to their activity along the body axis, an evolutionary conserved feature known as collinearity. In Drosophila, the BX-C cluster contains the three most posterior Hox genes, where their collinear activation incorporates progressive replacement of histone modifications, reorganization of 3D chromatin architecture and sequential activation of boundary elements and cis-regulatory regions. To dissect functional hierarchies, we compared chromatin organization in larvae and in cell lines, with a focus on the Abd-B gene. Our work establishes the importance of the Fab-7 boundary element for insulation between 3D domains marked by different histone modifications. Interestingly, we detected a non-canonical inversion of collinear chromatin dynamics at the Abd-B gene, with the active histone domain decreasing in size. This chromatin organization differentially instructed alternative Abd-B promoter use, thereby expanding the possibilities to regulate transcriptional output.Competing Interest StatementThe authors have declared no competing interest. ER -