Figure 1.

Expression Characteristics of the MC9 Gene and Molecular Characterization of the MC9 Transgenic Lines Used in This Study.

(A) to (D) GUS staining of root cap of 2-d-old seedlings (A), root cap of 1-week-old seedling (B), tracheary elements in expanding cotyledon (C), and petals prior to abscission (D).

(E) Schematic representation of the T-DNA insertion of the GK-540H0 allele. The catalytic His and Cys, the p20 and p10 MC9 protease subunits, and the linker region between the two catalytic subunits are depicted.

(F) Immunoblot analysis of Arabidopsis seedlings' proteins with a MC9 polyclonal antibody. Full-length 35.5-kD MC9 is detected in the wild type (Col-0) and 35S:MC9 overexpressor (Vercammen et al., 2006), but not in the mc9 knockout line (GK-540H0 allele). An actin antibody directed against a common epitope of all actin isoforms (Immuno, clone C4) was used as gel loading control.

(G) Transcript levels of all Arabidopsis metacaspase genes (MC1 to MC9) in 2-d-old seedlings. Values represent the mean of three measurements ± sd relative to the MC9 gene transcript level in the wild type (Col-0).