A unique transgenic mouse model exhibiting a myeloproliferative disease-like phenotype

Transmembrane protein 207 (TMEM207) is an important molecule involved in invasiveness of gastric signet ring cell carcinoma. To understand the pathobiological effects of TMEM207, we generated thirteen transgenic mouse lines, designated C57BL/6-Tg (ITF-TMEM207), where mouse TMEM207 is expressed heterotrophically, regulated by the proximal promoter of the murine intestinal trefoil factor (ITF) gene (also known as Tff3). A C57BL/6-Tg (ITF-TMEM207) mouse line unexpectedly exhibited a high incidence of a spontaneous condition resembling myeloproliferative disease-like phenotype. Increased numbers of CD117+ cells and appearance of dysplastic myeloid cells in bone marrow were observed. These histopathological features suggested human myeloproliferative disease or its precursor manifestations, and were found in almost all mice within 1 year. TMEM207 immunoreactivity was identified in megakaryocytes and erythroblasts of the transgenic mice. The ITF-TMEM207 construct was inserted into Atg4b on murine chromosome 1. Myeloproliferative disease was not observed in other C57BL/6-Tg (ITF-TMEM207) transgenic mouse lines. However, although several other genetically manipulated animal models of myeloproliferative disease and Atg4b knockout mice exist, this mouse line harboring a mutated Atg4b gene, and with overexpression of TMEM207 protein, has not been reported as a model of myeloproliferative disease to date. The present study demonstrated that the C57BL/6-Tg (ITF-TMEM207) mouse may be a valuable model for improved understanding of human myeloproliferative disease.