Fig. 7. GL1 is a target gene of TCL1. (A) Schematic showing the effectors and reporter constructs used in the Arabidopsis protoplast transfection assays. (B) TCL1-VP16 transactivator fusion protein activates the expression of the reporter. Effectors and reporters were cotransfected into protoplasts derived from Arabidopsis rosette leaves. GUS activity was assayed after protoplasts were incubated in the dark for 20-22 hours. (C) Leaves and stem trichome phenotypes of transgenic plants overexpressing TCL1-VP16. (D) RT-PCR analysis of the level of GL1, TTG1, GL3 and GL2 transcripts in plants overexpressing TCL1-VP16. Expression of ACTIN2 provided a control. (E) Chromatin immunoprecipitation (ChIP) assay. ChIP was performed with 35S:HA-TCL1 plants using anti-HA antibodies. Rabbit preimmune serum was used as a mock control. Primer sets specific for the first intron or the 3'-UTR region of GL1 were used in PCR reactions. ACTIN2 provided a control.