Mcf2^tm1Ehi

A cassette containing IRES-lacZ followed by neo was inserted in exon 1 after the start codon via homologous recombination. Transcript was undetected by RT-PCR analysis of testis and brain tissue, while Western blot analysis confirmed the absence of protein in testis, brain, and liver tissue. LacZ expression was undetected by Xgal staining, putatively due to a combination of the low activity of the endogenous promoter and the inefficiency of the IRES sequence. (J:78933)