Interaction of N1-substituted adenines with 1-methyladenine receptors of starfish oocytes in induction of maturation

Starfish oocytes are arrested naturally in the late G(2) phase of the first meiotic division. In response to the natural maturation-inducing hormone, 1-methyladenine (1-MA), oocytes undergo reinitiation of meiosis with germin al vesicle breakdown. We tested 10 newly synthesized NI-substituted adenine s that are 1-MA analogues to analyze, the interaction between 1-MA and its stereo-specific receptors on the oocyte plasma membranes of the starfish As terina pectinifera. Among these analogues, 1-(beta -naphthylmethyl)adenine, 1-aminoadenine and 1-(p-nitrobenzyl)adenine, played agonistic roles in the induction of oocyte maturation. 1-(o-Nitrobenzyl)adenine, 1-(m-nitrobenzyl )adenine, 1-phenethyladenine and 1-(p-nitrophenethyl)adenine had antagonist effects on 1-MA-induced oocyte maturation. These agonists and antagonists behaved competitively in the binding of [H-3]1-MA to receptors in oocyte co rtices. In contrast, 1-(alpha -naphthylmethyl)adenine, 1-(2,4-dinitrobenzyl ) adenine and 1-(p-methoxybenzyl)adenine had no effects on oocyte maturatio n. Our results suggest that regional-specific sterical structures at the N1 -site of adenine are important in the interaction between 1-MA and its rece ptors in oocytes. In addition, a negative charge at the N1-site of adenine is required for binding with the receptors. (C) 2001 Elsevier Science Inc. All rights reserved.