Rosacreert2

All protocols and experimental procedures were approved by the Institutional Animal Care and Use Committee (IACUC). Unc5B^fl/fl mice^{51 (link)} were bred with Cdh5Cre^ERT2 mice^{56 (link)} or PDGFRbCre^{ERT263 (link)} or ROSACre^ERT2 (Jackson laboratories), βcatenin GOF Ctnnb1^flex/3 mice, Ctnnb1^fl/fl mice, Robo^−/− mice and Ntn1^fl/fl mice were described previously^{10 (link),48 (link),50 (link),57 (link),72 (link)–74 (link)}. Inducible Netrin1 gain of function mice were generated by intercrossing loxStoplox;hNtn1^{62 (link)} with ROSACre^ERT2 (Jackson laboratories) driver to induce ubiquitous overexpression of Netrin-1. Gene deletion or overexpression were induced by injection of tamoxifen (Sigma T5648) diluted in corn oil (Sigma C8267). Postnatal gene deletion was induced by 3 injections of 100ug of tamoxifen at P0, P1 and P2 for analysis at P5, or by 3 injections of 100ug of tamoxifen at P6, P7 and P8 for analysis at P12

Zfp809^GT mice were generated by injection of 129S2/SvPas ESCs (German Gene Trap Consortium, no. F065A07), which contain a Zfp809 allele with a gene trap vector (pT1ATG βGeo) inserted between exons 1 and 2, into B6D2F2 blastocysts. Chimeric mice were intercrossed to obtain Zfp809^GT/+ and Zfp809^GT/GT mice. Zfp809^KO-first mice were generated by injection of C57/Bl6 ESCs harboring a conditional Zfp809 knockout allele (Knockout Mouse Project [KOMP] Repository, University of California at Davis) into C57/Bl6 blastocysts. Zfp809^KO-first mice were crossed with Flp mice (Jackson Laboratory, stock no. 003946) to facilitate germline FLP-FRT recombination and the birth of Zfp809^FL mice. Zfp809^FL mice were crossed with mice harboring either constitutively active Cre (Jackson Laboratory, stock no. 003724) or a 4-OHT-inducible RosaCreERT2 gene (Jackson Laboratory, stock no. 004847) to generate Zfp809 knockout mice or inducible Zfp809^FL/FL; RosaCreERT2 mice, respectively.