Fig. 2. Expression analysis of AtCAP-E1 and AtCAP-E2. RT-PCR was performed on total RNA from roots (R), stems (S), leaves (L), buds (B), and siliques (Si). (A) DNA gel blot of RT-PCR product pool. (B) PCR products were digested with Ssp I (AtCAP-E1-specific site) before DNA gel blotting. The intensity of the 662 bp fragment represents the relative abundance of the AtCAP-E1 transcript. (C) PCR products were digested with XbaI (AtCAP-E2-specific site) before DNA gel blotting. The intensity of the 459 bp fragment represents the relative abundance of the AtCAP-E2 transcript. (D) Ethidium bromide-stained gel of 1 µg of total RNA used for reverse transcription showing equal amounts of high quality total RNA. (E-I) AtCAP-E1 is expressed in meristems and mitotically active tissues. An AtCAP-E1::GUS reporter construct was introduced into wild-type Arabidopsis plants and GUS activity was examined in the transgenic plants. (E) GUS activity at the apex of an 8-day-old seedling. The apical dome and emerging true leaves stain intensely as does the tip of the root. (F) GUS activity in the primary root apical meristem and in early lateral root primordia (G) emerging from the pericycle cells. (H) GUS activity in developing leaves parallels the basipetal pattern of cell differentiation. (I) intense GUS activity in young floral buds.