Nuclear localization of magphinins, alternative splicing products of the human trophinin gene

作者：Aoyama Junya; Akazawa Yusuke; Kasahara Kousuke; Higashiyama Yukihiro; Kikuchi Ikue; Fukumoto Yasunori; Saburi Sakura; Nakayama Yuji; Fukuda Michiko N^*; Yamaguchi Naoto

来源：Journal of Cellular Biochemistry, 2008, 103(3): 765-777.

DOI：10.1002/jcb.21446

• magphinin
• trophinin
• MAGE
• alternative splicing
• nuclear localization
• nuclear matrix

Human magphinin proteins are translation products of differentially spliced transcripts from the 5' region of the human trophinin gene (TRO), whose 3' region encodes trophinin, a unique cell adhesion molecule involved in human embryo implantation. Magphinins belong to the MACE (melanoma-associated antigen) family, and a previous study of mouse magphinins showed their expression in male and female germ cells, suggesting a role in germ cell development. Here, we characterized the structure and subcellular localization of human magphinins. Confocal microscopy analysis of ectopically expressed magphinins revealed that magphinin-alpha and -beta localize in the cytoplasm, whereas magphinin-gamma lacking the peptide encoded by exon-3 is nuclear. Following Triton X-100 extraction, DNA digestion, and high salt extraction magphinin-gamma remained nuclear, suggesting strong association with the nuclear matrix. A series of magphinin-gamma deletion mutants were generated and assayed for localization, which showed that the N-terminal region of the MACE homology domain is necessary for nuclear localization. When magphinin-gamma was expressed in NIH3T3 cells, cells underwent G1 arrest. These results suggest that human magphinin-gamma inhibits cell cycle progression through nuclear activity.

• 出版日期2008-2-15
• 单位河北医科大学