Transgenerational analysis of transcriptional silencing in zebrafish

► Widely used 14X UAS is transcriptionally silenced in transgenic zebrafish. ► CpG methylation at the 14X UAS causes silencing of transgene expression. ► Transgenes integrated near transposons are rapidly silenced in the first generation. ► New, less repetitive 4X UAS reduces transgene silencing and methylation. ► High reporter expression persists for at least three generations using new 4X UAS.