Fig. 2.

Tissue-specific distribution of castor PTPC and BTPC transcripts and polypeptides and PEPC specific activity. (A) Semi-quantitative RT-PCR analysis of RcPpc1, RcPpc3, and RcPpc4 gene expression in castor. PEPC transcript levels were measured in various tissues using primers specific for the three castor PEPC genes. Starting template levels were adjusted to normalize RcActin band intensity, which served as a control for equal template loading. Primers pairs for RcPpc1, RcPpc3, RcPpc4, and RcActin yielded fragments of the expected size. (B) Clarified extracts were subjected to SDS-PAGE and immunoblotting. For anti-PTPC, anti-pSer11, and anti-BTPC immunoblots, lanes with developing COS extracts contained 5, 25 or 10 μg of protein, respectively, whereas all other lanes contained 10, 50 or 40 μg of protein, respectively. (C) Specific PEPC activities represent the means ±SE of duplicate determinations on a minimum of three biological replicates. Abbreviations are as described in the legend to Fig. 1 in addition to the following: dC and dE, cotyledon and endosperm, respectively, from stage VII developing COS that had been depodded for 72 h.