Sponge homologue to human and yeast gene encoding the longevity assurance polypeptide: differential expression in telomerase-positive and telomerase-negative cells of Suberites domuncula

Porifera show a characteristic Bauplan in spite of the fact that (almost) a ll cells are telomerase-positive and presumably provided with an unlimited potency for cell proliferation. Studies revealed that telomerase-positive c ells can be triggered to telomerase-negative cells by dissociating them int o single cells. Single cells from the demosponge Suberites domuncula, in co ntrast to cells present in primmorphs (a special form of cell aggregates), lack the property to proliferate and they undergo apoptosis. One gene, SDLA GL, was identified in primmorphs that showed high sequence similarity to th e longevity assurance genes from other Metazoa. In single cells no transcri pts of SDLAGL could be identified, while high expression was seen after re- aggregation of single cells and in proliferating cells of primmorphs. We co ncluded that SDLAGL is involved in the shift of telomerase-positive, prolif erating cells to telomerase-negative, non-proliferating cells. (C) 2000 Els evier Science Inland Ltd. All rights reserved.