Expression pattern of OsUBP15 and subcellular localization of OsUBP15. A, Schematic domain structure of OsUBP15. OsUBP15 harbors a MYND-type zinc finger (ZnF-MYND) motif (in yellow box) at the N terminus and a UCH motif (in black box) at the C terminus. The line indicates the mutant site in Osubp15. B, Relative expression of OsUBP15 in various tissues including seedlings, leaf blades, stems, leaf sheaths, young panicles, and brown grain (3 DPA). The rice Ubiquitin gene was used as an internal control. Data are means ± sd (n = 3). C, GUS staining of pOsUBP15:GUS transgenic T1 plants. GUS activity was detected in roots at the germination stage (a), stems (b and e), sheaths (c), leaves (d), young panicles (f), glumes (g and h), and the caryopsis at the filling stage (i), the cross section of the caryopsis at filling stage (j). Bars = 5 mm (a) and 2 mm (b–j). D, Grain morphologies of the wild type (WT), empty GFP, and gOsUBP15-GFP transgenic T1 lines. Bar = 5 mm. E, Localization of OsUBP15-GFP in the cytoplasm and nucleus in young roots of a gOsUBP15-GFP transgenic T1 line. Bars = 20 μm.