THE (2'-5')OLIGOADENYLATE SYNTHETASE IS PRESENT IN THE LOWEST MULTICELLULAR ORGANISMS, THE MARINE SPONGES - DEMONSTRATION OF THE EXISTENCE AND IDENTIFICATION OF ITS REACTION-PRODUCTS

We have proved the presence of (2'-5')oligoadenylates [(2'-5')A(n)] an d oligoadenylate synthetase [(2'-5')A(n) synthetase] in the marine spo nge Geodia cydonium. (2'-5')A(n) isolated from sponge crude extract co mpeted with authentic (2'-5')A(n) for binding to polyclonal antiserum against (2'-5')A(n) HPLC analysis revealed the presence of nucleotides eluting with molecular markers for (2'-5')A oligomers. The biological activity of sponge (2'-5')A(n) was demonstrated by inhibiting the pro tein biosynthesis in rabbit reticulocyte lysate. The activity of the ( 2'-5')A(n) synthetase, present in crude sponge extract, was found to b e high compared to that in mammalian interferon-treated cell extract. The (2'-5')A(n) synthetase from sponge extract binds to poly(I). poly( C) as does the mammalian enzyme. Western blot analysis with antibodies to recombinant rat 43-kDa (2'-5')A(n) synthetase revealed in sponge i mmunologically related proteins with molecular masses of approximately 110, 65, 61 and 34 kDa. We conclude, that the (2'-5')A(n) system has evolved from receptors and enzymes involved in cell adhesion and/or gr owth control.