The human BAC clone RP11-1376P16 containing the CSNK1D gene was targeted to generate a threonine-to-alanine mutation at amino acid 44 in the protein (T44A). An IRES-GFP cassette was also inserted after the stop codon of the CSNK1D gene. Six lines were generated with 4 of the lines 498, 503, 816 and 830, being low expressers due to insertion of only one copy of the transgene. Transgene expression was confirmed by RT-PCR of brain lysates. This is a representative record for the four low expressing lines. (J:97658)