Fig. 1

Identification of RSPO2 as a NOBOX target and in vitro assay of NOBOX transcriptional activity using RSPO2 promoter as reporter gene. a Schematic map of 954 bp promoter sequence of human RSPO2 including 2 NOBOX binding elements (NBE) located at −3370 and −2898 upstream of the transcription site. b NOBOX activity is shown as the luciferase activity above baseline, which is defined as the activity observed in cells transfected with empty vector (Ctl). The transcriptional activity of wild-type NOBOX (NOBOX WT) was studied using RSPO2 promoter transfected in COS7 cells. As a negative control, the NOBOX deleted homeodomain mutant (NOBOX-303X) was used. Results are presented as mean ± SEM of 3 independent experiments each performed in sixplicate. **P < .01 ****P < .0001. RLU, relative light units