TY - JOUR TI - CRISPR/Cas9 and active genetics-based trans-species replacement of the endogenous Drosophila kni-L2 CRM reveals unexpected complexity AU - Xu, Xiang-Ru Shannon AU - Gantz, Valentino Matteo AU - Siomava, Natalia AU - Bier, Ethan A2 - Patel, Nipam H VL - 6 PY - 2017 DA - 2017/12/23 SP - e30281 C1 - eLife 2017;6:e30281 DO - 10.7554/eLife.30281 UR - https://doi.org/10.7554/eLife.30281 AB - The knirps (kni) locus encodes transcription factors required for induction of the L2 wing vein in Drosophila. Here, we employ diverse CRISPR/Cas9 genome editing tools to generate a series of targeted lesions within the endogenous cis-regulatory module (CRM) required for kni expression in the L2 vein primordium. Phenotypic analysis of these ‘in locus’ mutations based on both expression of Kni protein and adult wing phenotypes, reveals novel unexpected features of L2-CRM function including evidence for a chromosome pairing-dependent process that promotes transcription. We also demonstrate that self-propagating active genetic elements (CopyCat elements) can efficiently delete and replace the L2-CRM with orthologous sequences from other divergent fly species. Wing vein phenotypes resulting from these trans-species enhancer replacements parallel features of the respective donor fly species. This highly sensitive phenotypic readout of enhancer function in a native genomic context reveals novel features of CRM function undetected by traditional reporter gene analysis. KW - in-locus KW - active genetics KW - CRISPR KW - knirps KW - Drosophila KW - wing vein JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -