Figure 2. Nkx6.1 interferes with Pax6-mediated transcriptional activation of the glucagon gene promoter.

(A) BHK-21 cells were co-transfected with 10–μg of the indicated reporter plasmids and 0.25–μg of expression vectors encoding Pax6 either alone or with 0.03–0.25–μg of Nkx6.1 expression vector. Nkx6.1 (0.25–μg) was transfected alone as a control. (B) BHK-21 cells were co-transfected with 10–μg of the indicated reporter plasmids and 0.25–μg of expression vectors encoding Cdx2/3 either alone or with 0.03–0.25–μg of Nkx6.1 expression vector. Nkx6.1 (1–μg) was transfected alone as a control. (C) BHK-21 cells were co-transfected with 10–μg of the indicated reporter plasmids and 0.25–μg of expression vectors encoding Pax6 and 0.25–μg of Cdx2/3 either alone or with 0.03–0.5–μg of Nkx6.1 expression vector. Nkx6.1 (1–μg) was transfected alone as a control. (D) BHK-21 cells were co-transfected with 10–μg of either −138GluCAT or −31GluCAT along with 0.25–μg of expression vectors encoding c-Maf alone or in combination with 0.06–0.5–μg of Nkx6.1 expression vector. Nkx6.1 (1–μg) was transfected alone as a control. (E) BHK-21 cells were co-transfected with 10–μg of the indicated reporter plasmids and 0.25–μg of expression vectors encoding Pax6 and c-Maf either alone or with 0.06–1–μg of Nkx6.1 expression vector. Nkx6.1 (1–μg) was transfected alone as a control. Data are presented as relative CAT activity. * and ** indicate statistical significance with P<0.05 and P<0.02 respectively.