Figure 3.

Expression pattern and cysteine protease activity analysis of OCP. (A) OCP RNA expression pattern obtained by qRT-PCR in rice TP309 (mean ± SEM, n = 3). (B) GUS activity of OCP in different rice tissues. a, node; b, axillary bud; c, leaf; d, root; e, sheath; f, stem; g, panicle; h, leaf and sheath of seedlings. Scale bars: a = 5 mm; b = 2 mm; c–h = 10 mm. (C) Subcellular localization of OCP in rice root tips and rice protoplasts. Scale bar = 10 μm. (D) Protease activity profiling of OCP in vitro. E-64 was an effective inhibitor of cysteine proteases, and DCG-04 was a biotinylated derivative of E-64. The biotinylated protease could be detected on a protein gel blot using a conjugate of streptavidin with HRP (strep.-HRP). OCP-His was detected with Anti-His.