Enzymatic activity of GIF1 and OsCIN1. (A) The GIF1 and OsCIN1 transcript levels in leaves detected by RT-PCR showing GIF1 and OsCIN1 overexpression in transgenic lines (left). Each one line of GIF1-OE and OsCIN1-OE was analyzed for GIF1 and OsCIN1 transcript levels respectively, with 25 PCR cycles (right). Ubi-1, a loading control for RT-PCR with 24 cycles. Note that line OsCIN1-OE-2 accumulated higher level of OsCIN1 transcripts than the level of GIF1 transcripts in line GIF1-OE-42. (B) CWI activity in leaves of the OsCIN1-OE and GIF1-OE plants and the empty vector control. C. Multiple sequence alignment of two conserved regions of cell wall invertases in maize, rice and yeast. The NDPNG domain and Asp-239/Lys-242 are shown in bold. The amino acid difference between GIF1 and OsCIN1 are shown in red color.