FIG. 4.

Progressive silencing of Ddc_exon1a during mouse postnatal development. (A) Northern blot analysis of mouse Ddc expression in total RNA extracted from e13.5 embryo, newborn heart, 4-week heart, and 3-month heart, showing a 2-kb transcript. (B) RT-PCR analysis of Ddc_exon1a expression in newborn heart and 3-month heart cDNAs using the primers EXON1A-F and EXON6-R (see Materials and Methods), which amplify a 786-bp product. The 500-bp marker is indicated for a reference (arrows). RNA integrity was verified by amplification of β-actin sequences from each sample, and samples treated with (+) and without (-) reverse transcriptase are indicated.