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It has been suggested that metastasis-associated proteins 1 and 2 (MTA1 and MTA2) are capable of suppressing estrogen receptor alpha (ERα) transactivation activity in breast cancer cells. ERα, which is present in the epididymis, is a crucial mediator of maintaining the luminal environment necessary for proper sperm maturation and function. The present study was undertaken to analyze the expression profile of both MTA1 and MTA2 in the epididymis of rats and to ascertain whether MTA1/2 colocalizes with ERα in the epididymis and primary cultured epididymal epithelial cells. Reverse transcription polymerase chain reaction (RT-PCR), Western blotting and immunohistochemistry analyses were utilized to demonstrate that MTA1 and MTA2 are expressed in the epididymis. Furthermore, these analyses revealed that MTA1 and MTA2 are predominantly localized in the nuclei of almost all epididymal epithelial cells. Immunofluorescence staining revealed that MTA1/2 colocalizes with ERα in epididymal epithelial cells. In conclusion, MTA1 and MTA2 are expressed in the epididymis of rats; these proteins colocalize with ERα in epididymal epithelial cells, suggesting that MTA1 and MTA2 may be involved in the regulation of ERα transactivation activity in the epididymis of rats to facilitate a stable environment in the lumen.

113 Cd NMR spectroscopy was employed to investigate the interactions between aromatic C–H and the coordinated sulfur atom in the neutral four-coordinated cadmium(II) complexes, [Cd{S-2-(4-X-C 6 H 4 CONH)C 6 H 4 } 2 (1-MeIm) 2 ] (X=H, OMe, F and CN; 1-MeIm=1-methylimidazole). The coordinating atom set here is S 2 N 2 that is similar to the zinc and iron sites in the known metalloproteins such as zinc finger and ferredoxins, respectively. The observation of 113 Cd NMR signals in the range 480–420 ppm in chloroform at 298 K indicates that the cadmium(II) ion is bound with the S 2 N 2 donor set in solution. The complex without substituent (i.e. X=H) exhibits a 113 Cd NMR signal at 475 ppm while the analog with the strongest electron-withdrawing cyano substituent gives a signal at 424 ppm in chloroform at 298 K. The chemical shifts of cadmium(II) complexes with a variety of substituents had a linear correlation with the Hammett σ m values rather than the σ p values, although the substituents are at the para -position of the benzoyl group. The results demonstrate that there are aromatic C–H---S interactions between the protons of the benzoyl group and the coordinated sulfur atom in the cadmium(II) complexes with S 2 N 2 binding site, in addition to the NH---S hydrogen bonds which were confirmed by infrared and 1 H NMR spectroscopies.