RT Journal Article SR Electronic T1 An efficient FLP-based toolkit for spatiotemporal control of gene expression in Caenorhabditis elegans JF bioRxiv FD Cold Spring Harbor Laboratory SP 107029 DO 10.1101/107029 A1 Celia María Muñoz-Jiménez A1 Cristina Ayuso A1 Agnieszka Dobrzynska A1 Antonio Torres A1 De la Cruz Ruiz Patricia A1 Askjaer Peter YR 2017 UL http://biorxiv.org/content/early/2017/02/08/107029.abstract AB Site-specific recombinases are potent tools to regulate gene expression. In particular, the Cre and FLP enzymes are widely used to either activate or inactivate genes in a precise spatiotemporal manner. Both recombinases work efficiently in the popular model organism Caenorhabditis elegans but their use in this nematode is still only sporadic. To increase the utility of the FLP system in C. elegans we have generated a series of single-copy transgenic strains that stably express an optimized version of FLP in specific tissues or by heat induction. We show that recombination efficiencies reach 100 percent in several cell types, such as muscles, intestine and serotonin producing neurons. Moreover, we demonstrate that most promoters drive recombination exclusively in the expected tissues. As examples of the potentials of the FLP lines we describe novel tools for induced cell ablation by expression of the PEEL-1 toxin and a versatile FLP-out cassette for generation of GFP-tagged conditional knockout alleles. Together with other recombinase-based reagents created by the C. elegans community this toolkit increases the possibilities for detailed analyses of specific biological processes at developmental stages inside intact animals.