A multi-TM Setaria italica SiRGS1 gene. (A) SiRGS1 gene structure. Red or black boxes show DNA regions homologous to AtRGS1 with or without experimental support of EST transcription data. Two transposon DNAs, LTR retrotransposon alubu and LINE, are indicated with blue lines. Red arrows indicate the location of the primers used to amplify the SiRGS1 gene. Supplementary figure S1, Supplementary Material online, shows the predicted protein products of the SiRGS1 locus. (B) Expression of SiRGS1, SiGPA1, and SiACT1 genes in S. italica leaves and roots. The indicated cDNA or genomic DNA was prepared from 14-week-old S. italica leaves or roots. Using RT-PCR as described in Materials and Methods, the presence of mRNA encoding the cytoplasmic RGS box of SiRGS1 was compared with the presence of RNA encoding SiGPA1 or actin (SiACT1) was tested.