A 15kDa selenoprotein (Sel-15) has recently been discovered, the function of which is still unknown. Sel-15 does not contain any common motifs, nor it is homologous to other known proteins. Our study is aimed at characterizing this novel protein and examining its possible function in cells....[ Read more ]

A 15kDa selenoprotein (Sel-15) has recently been discovered, the function of which is still unknown. Sel-15 does not contain any common motifs, nor it is homologous to other known proteins. Our study is aimed at characterizing this novel protein and examining its possible function in cells.

In this project, protein sequence in-silico analysis, human multi-tissue expression mRNA dot blot array, immunohisto-staining, flow cytometry analysis, Sel-15 over- expression and yeast two hybrid system were applied to study Sel-15. Results show that Sel-15 was expressed in all tissue samples with higher expression level in prostate and thyroid glands. It was found that Sel-15 was an α-helix dominant protein without a transmembrane domain and predominantly localized in cytoplasm. Sel-15 expression level in the transformed cell line was 1 fold higher than that in the cancer cell line. Moreover, morphological changes were observed in the Sel-15 over-expressed cancer cell line, and these changes might be due to the varied expression of cell adhesion molecules. Results from yeast two hybrid system detected that Sel-15 interacted with five different clones. In summary, Sel-15 exists in a large variety of human tissues with different expression levels. The function of Sel-15 may be related to its protein expression level. Further experiments are required to explore its possible functional role and its regulatory pathway in cells.