PMP22 is expressed in the endometrium. (A). Frozen adult human tissues were obtained, and total RNA isolated. PMP22 exon 1B mRNA was expressed in endometrium, lung, and tonsil tissue while expression of PMP22 exon 1B mRNA was only observed in the lung. GAPDH mRNA was used as the loading control. (B) Tissue lysates were prepared to determine PMP22 protein expression in the endometrium. PMP22 protein was detectable in proliferative endometrium, and a representative sample is depicted. N = 6. (C) PMP22 expression was confirmed in human proliferative endometrium using immunohistochemistry, and a representative sample is displayed. N = 6. Magnification = 400 ×. (D) PMP22 mRNA transcripts were detected in HEC-1A, Ishikawa, and RL95-2 endometrial cell lines using semi-quantitative RT-PCR. GAPDH was used as a loading control. (E) PMP22 protein levels in the three immortalized endometrial cell lines were detected using PMP22 antisera. β-actin was used as a loading control. (E) To study PMP22 in HEC-1A epithelial cells, its expression was modulated through ectopic overexpression, or by inhibition using a PMP22 specific siRNA. Vector and scrambled siRNA controls are included for endogenous expression. Expression of PMP22 was confirmed by western blot analysis, with β-actin levels serving as a loading control.