Fig. 2. Deletion in promoter region of Fpn1 leads to altered transcriptional initiation, but not transcript abundance, in Pcm mutant mice. (A) A 58 bp deletion in the promoter region of Fpn1 constitutes the Pcm mutation. Black arrowheads indicate wild-type transcription initiation site determined by 5'RACE, red arrowheads indicate Pcm/Pcm initiation sites. ATG, translational start; IRE, iron responsive element; boxed region indicates TATA box. (B) Mutant phenotype co-segregates with deletion in Fpn1, as demonstrated by PCR genotyping using primers indicated by overlined and underlined sequences in A. Wild-type band 230 bp; mutant band 172 bp. (C) 5'RACE PCR demonstrates altered Fpn1 transcript identity in Pcm mutant mice. Wild-type band 630 bp. (D) Real-time RT-PCR to quantify Fpn1 transcript abundance reveals no statistically significant difference among genotypes at 3 weeks of age. The horizontal line indicates the median.