This allele from IMPC was generated at UC Davis by injecting CAS9 RNA and 4 guide sequences TGAGTTCAATATGGTGCTAGGGG, TGTACCTGGAAAAAACCTAGGGG, CCAGAGGACAATTAGTCATCACT, CCTTAAGTTCAAGCACAGGAACA, which resulted in an Exon Deletion. Exon 3 (ENSMUSE00001236831) and flanking splicing regions were deleted. RT-PCR analysis confirmed the absence of Rbbp4 expression in homozygous mutant blastocysts.