The floxed neo cassette was removed from Fancatm1Wong via cre-mediated recombination, leaving the IRES-NLS-lacZ sequence in place of exons 1 through 6. While transcript containing the targeted exons was undetected, RT-PCR analysis of homozygous mutant mice revealed transcript that included exons 14 through 18. A C-terminal antibody was not available to determine if protein was produced from the detected message. (J:85108)