Trp53^tm1Ldo

Insertion of a PGK-hypoxanthine phosphoribosyltransferase (HPRT) expression cassette introduced into exon 7 an A-to-T mutation that results in a p.Arg245Trp substitution, and deleted 20 kb of sequence that included exons 1-6 and a large undefined upstream region. The authors propose that an unknown upstream promoter initiates a chimeric mRNA containing a 55-nucleotide leader spliced onto exons 7-11. This mRNA contains three in-frame AUG codons. The third AUG codon is a viable translation initiation site, which may produce a C-terminal protein fragment. RT-PCR analyses detect expression of this allele in several tissues of heterozygous mutant mice, albeit at lower levels than the wild-type allele. Studies of in vitro transcription and translation of a construct containing cDNA from this allele detected expression of a predicted 24 kDa protein. (J:73757)