Detection of estrogen receptor mRNA in human uterus

We transcribed a cDNA clone of the human estrogen receptor (ER) with T7 RNA polymerase. The ³²P-cRNA transcript complementary to ER mRNA was hybridized to poly(A)⁺ RNA from human uterus and revealed a single band of ≈ 4.2 kilobases. No hybridization was seen with the cRNA probe of the opposite orientation. Hybridization of total RNA from calf and rat uterus yielded a single band at ≈ 3.8 kilobases for both species. Total RNA from rat spleen did not hybridize. A ³⁵S-labeled cRNA probe was prepared for in situ hybridization of ER mRNA in human uterus and spleen. Autoradiographic signal was present over endometrial epithelium, stromal cells of the lamina propria, and smooth muscle cells of the myometrium but was absent from sections of spleen. The ER mRNA hybridization label was located over cytoplasm and nuclei of uterine target cells.