Different nuclear/cytoplasmic distributions of RET finger protein in different cell types

The RET finger protein (RFP), which belongs to the B box zinc finger protei n family, has a tripartite motif consisting of a Ring finger, a B box finge r and a coiled-coil domain. The RET finger protein becomes oncogenic when i ts tripartite motif is fused with the tyrosine kinase domain of the RET pro tein. This study examined the RFP expression in normal and tumor tissues by immunohistochemistry. RFP was detected in the nuclei of various cells, inc luding peripheral and central neurones, hepatocytes, adrenal chromaffin cel ls and male germ cells, Among them, RFP was expressed at high levels in mal e germ cells such as primary spermatocytes and round spermatids, and formed a perinuclear cap structure in primary spermatocytes, On the other hand, h igh levels of cytoplasmic expression of RFP were observed in some plasma ce lls as well as solitary plasmacytoma and multiple myeloma, These results su ggested that different nuclear/cytoplasmic distributions of RFP might play a role in the regulation of growth or differentiation of different cell typ es.