PRIMARY STRUCTURES OF SPERM-SPECIFIC BASIC NUCLEAR PROTEINS AND GENE-EXPRESSION IN JAPANESE NEWT, CYNOPS-PYRRHOGASTER

Electrophoretic analyses of acid extracts from mature sperm of newt, C ynops pyrrhogaster, on acid/urea/Triton X-100 polyacrylamide gel showe d the exclusive occurrence of sperm-specific nuclear basic proteins (S BPs), which moved faster than somatic histones on the gel. These SBPs were eluted separately by reversed phase-high-performance liquid chrom atography as two large peaks and a few small peaks. Of these, only the small peaks disappeared with treatment of the acid extracts with alka line phosphatase before they were injected into the column, so that th ere were only two distinct components: NP1 and NP2. Determination of a mino acid sequences by the Edman method as well as by sequencing of cD NA for both components indicated that each protein consisted of 43 (NP 1) or 48 (NP2) amino acid residues, rich in arginine residues (53.5% i n NP1; 47.9% in NP2), forming the clusters. They had molecular masses of 5,386 Da (NP1) acid 5,748 Da (NP2), respectively. Northern blot ana lysis using cDNAs as probes indicated that mRNAs for both NP1 and NP2 occurred not in primary spermatocytes but in round spermatids. In situ hybridization analyses using antisense RNA for NP1 as a probe clearly showed the first appearance of NP1 mRNA at the late stage of round sp ermatid. (C) 1997 Wiiey-Liss, Inc.