Cell Differentiation, 24 (1988) 209-214 209 Elsevier ScientificPublishers Ireland, Ltd. CDF 00519 Stress proteins by zinc ions in sea urchin embryos M.C. Roccheri 1, M. La Rosa 1, M.G. Ferraro 1, M. Cantone 1, D. Cascino 1, G. Giudice 1,2 and G. Sconzo i I Dipartimento di Biologia Cellulare e dello Sviluppo and 2 lstituto di Biologia dello Sviluppo del CNR, Via Archirafi no. 20-22, 90123 Palermo, Italy (Accepted 21 March 1988) In Paracentrotus lividus embryos, treatment with zinc ions induces the synthesis of the two major stress proteins with the same molecular weight as those induced by heat shock. The developmental stages responsive to zinc ion treatment are the same as those responsive to heat shock. However, zinc treatment induces a longer lasting synthesis of the stress proteins, and, unlike heat shock, does not induce thermotolerance and does not inhibit synthesis of the bulk proteins. Paracentrotus lividus; Embryo; Stress protein; Zinc ion Introduction In the cells of all the organisms so far ex- amined, exposure to high temperature produces changes in gene activity with production of a small number of new proteins, the so-called heat shock proteins (h.s.p.) (for reviews see Schlesinger et al., 1982; Atkinson and Walden, 1985; Lind- quist, 1986). A wide variety of environmental stresses (chem- ical or physical) also produce the same cellular effect (Plesset et al., 1982; Li, 1983; Courgeon et al., 1984; Li and Laszlo, 1985; Whelan and High- tower, 1985; Heikkila et al., 1987). Since sea urchin embryos respond to heat treatment by synthesiz- Correspondence address: G. Sconzo, Dipartimento di Biologia Cellulare e dello Sviluppo,Via Archirafino. 22, 90123 Palermo, Italy. ing h.s.p, only if treated at specific developmental stages (Giudice et al., 1980; Roccheri et al., 1981a,b, 1982, 1986; Sconzo et al., 1983, 1985, 1986), we decided to investigate whether they re- spond to chemical stress by synthesizing h.s.p, at the same stages specific for heat shock. We chose to examine the effect of zinc ions, because the morphogenetic changes induced dur- ing sea urchin embryonic development have long been studied (for reviews see Giudice, 1973, 1986). It is indeed well known that sea urchin embryos reared in the presence of zinc ions from fertiliza- tion develop into the so-called 'animalized' blastulae in which an imbalance between struc- tures deriving from the animal half versus those deriving from the vegetal half is observed. Striking changes of gene expression following zinc treat- ment of sea urchin embryos have recently been reported by Nemer (1986), who has described the stimulation of metallothionein synthesis by zinc ions. 0045-6039/88/$03.50 © 1988 Elsevier ScientificPublishers Ireland, Ltd.