The Zdhhc9 gene consists of 10 exons. Coding exon 1 was targeted (NCBI accession NM_172465.1) by homologous recombination, whereby a genomic region of 207 bp including most of the first coding exon (exon2) was deleted. A selection cassette containing both neomycin and lacZ was also inserted. Western blot analysis of whole brain lysates confirmed the absence of full-length and any truncated protein fragment.