HMGI-C gene expression is not required for in vivo thyroid cell transformation

We have previously demonstrated that HMGI proteins are required for the tra nsformation of rat thyroid cells by v-mos and v-ras-KI oncogenes. To determ ine whether HMGI proteins are also required for in vivo thyroid carcinogene sis, mice carrying a disrupted HMGI-C gene (pygmy mice) were either treated with radioactive iodine or crossed with transgenic mice carrying the E7 pa pilloma virus oncogene under the transcriptional control of thyroglobulin g ene promoter, The pygmy mice developed thyroid carcinomas with the same fre quency as occurred in wildtype mice without significant macroscopic and mic roscopic differences. Therefore, these results indicate that HMGI-C gene ex pression is not required in in vivo thyroid cell malignant transformation.