Add2^tm1Llp

A neomycin resistance cassette replaced a genomic fragment containing exons 9 to 13. Western blot analysis did not detect protein in RBC ghosts from homozygous mutant mice. Northern blot analysis using a probe for exons 9 to 12 did not detect transcript in homozygous mutant brain, spleen, or kidney. Northern blots using a neoR gene probe indicated that in homozygous mutant mice, transcripts are produced from antisense neoR sequence, and in spleen membranes the 4kb chimeric transcript is translated into a 55kDa protein that is detectable by Western blot. RT-PCR analysis detected a transcript that is a direct splice from exon 8 to exon 14, and which in homozygous mutant brain and spleen does not produce a polypeptide that is detectable by Western blot analysis. (J:71029)