Generation of the rGH-ffLuc-eGFP (“Glowing Head”) genetically engineered mouse.

<p><b>A</b>, Structure of the expression vector for generation of Glowing Head (GH) transgenic mice. Expression of a firefly luciferase-eGFP fusion gene (ffLuc-eGFP) was targeted to the mouse anterior pituitary gland by using the rat growth hormone promoter (rGH) and human growth hormone gene sequences, which include a polyadenylylation site (hGHpA)²⁰. <b>B</b>, Optical expression pattern of transgene in GH mice as visualized by BL imaging. Reporter activity was detected in the anterior pituitary gland of both genders and the testes of male mice. <b>C</b>, Serum levels of growth hormone from age-matched GH mice and wildtype (WT) c-Brd mice was assessed by ELISA (mean ± SE). Blood was withdrawn at the same time of day. No significant differences in circulating growth hormone levels between the GH and WT mice were found. <b>D</b>, ffLuc-eGFP-labeled LLC tumors were subcutaneously transplanted into WT, GH, and NOD-SCID mice. Blood was withdrawn to prepare sera when tumors reached 500 mm³, and the serum levels of anti-GFP antibody were analyzed by ELISA. The levels of anti-GFP antibody in WT mice are significantly higher than those in GH and NOD-SCID mice (p<0.005), but no difference was found between those in GH and NOD-SCID mice (p = 0.19). The sera from healthy mice without tumor transplantation served as controls to define zero point.