Figure 4.

Expression of Cnx1 in Arabidopsis and N. plumbaginifolia.

(A) Expression of recombinant and endogenous Arabidopsis Cnx1. His-tagged Cnx1 (rCnx1) was separated on a 10% SDS–polyacrylamide gel and visualized by staining with Coomassie blue (lane 1, 2 μg) or by immunoblotting (lane 3, 0.1 μg). Fifty micrograms of crude protein extract from Arabidopsis plants was loaded in lane 4 (crude) and immunoblotted with polyclonal Cnx1 antibodies (Ak90cnx1; 1:2000 dilution). All other Cnx1 protein gel blots were performed under the same conditions. The discrepancy between the calculated molecular mass of Cnx1 (73 kD) and the observed migration in the gel (90 kD) reflects the greater mobility of the standard used (lane 2) and a lower SDS/protein ratio for denatured Cnx1.

(B) Cnx1 protein gel blot analysis of crude protein extracts (50 μg) from different Arabidopsis organs (lanes 2 to 6) and from a N. plumbaginifolia plant (lane 1).

(C) Cnx1 protein gel blot analysis of crude protein extracts from Arabidopsis wild-type and chl-6 mutant plants (B73) cultured on ammonium (NH₄⁺)- or nitrate (NO₃⁻)-containing culture medium either otherwise unsupplemented (−) or supplemented with 0.1 mM sodium molybdate (Mo) or 0.1 mM sodium tungstate (W).