Ubiquitin Interaction Motif Containing Protein 1 (UIMC1)

The N-terminal half of RAP80 contains 2 nuclear localization signals and a putative ubiquitin interaction motif. Northern blot analysis detected a major 2.6-kb transcript expressed highly in testis and moderately in ovary, thymus, and heart. In situ hybridization of mouse testis detected Rap80 associated with germ cells, with little expression in surrounding Leydig cells. No significant differences in the level of Rap80 were found between developmental subpopulations of germ cells, suggesting that Rap80 expression is not developmentally regulated. Immunofluorescence localization detected RAP80 in a speckled nuclear distribution in a transfected monkey kidney cell line, and mutation analysis indicated that the second nuclear localization signal directed intracellular localization.