Full-length coding regions of zebrafish smarcad1 genes were amplified by RT-PCR using gene-specific primers designed according to the current DNA sequence in Ensembl. Phusion® High-Fidelity DNA Polymerase master mix (New England Biolabs) was used for PCR amplification. PCR primers used here are listed in Table S1. The PCR products were purified using Zymo Gel Extraction Kit (Zymo Research) before they were cloned into the pJet1.2 vector using the CloneJET PCR Cloning Kit (Thermo Scientific). Gene inserts orientation was verified by Sanger sequencing. Riboprobes were synthesized through in vitro transcription using T7 DNA polymerase (New England Biolabs) and DIG RNA Labeling Mix (Roche). Then, the riboprobes were purified by SigmaSpin™ post-reaction clean-up columns (Sigma, S5059). Whole-mount in situ hybridization was carried out according to our previously published method.54 (link),55 (link) For histological analysis, post-hybridization embryos were equilibrated in 15% sucrose, then 30% sucrose in 20% gelatin, after which they were embedded in 20% gelatin for cryosectioning (6–12 μm). Images were acquired using AxioCam MRc camera on Zeiss SteREO Discovery.V12 and Axio Imager 2 compound microscope.