Characterization of SNP, a novel tissue- and phase-specific nuclear protein expressed during the proliferative phase in the oviduct of the lizard Podarcis sicula Raf.

The amino acid sequence of a novel tissue- and phase-specific nuclear prote in (SNP) has been determined, after purification from the nuclei of the ovi duct of the lizard Podarcis sicula Raf. during the reproductive period of t he seasonal growth. SNP has a pi of 9.0 and contains 81 amino acid residues with a molecular weight of 9211.88 +/- 0.09. It shows a bipartite organiza tion as the first 40 amino acids contain all 8 cysteinyl residues, while th e last 41 amino acids contain 16 prolyl residues. Two more components have also been identified and characterized, with the first 79 amino acids match ing SNP and missing one or two residues at the C-terminus. They have thus b een named [des-(Ala(81)) SNP1] and [des-(Lys,-Ala(81)) SNP1], respectively. The molecular weights are 9140.21 +/- 0.83 for [des-(Ala(81)) SNP1] and 90 11 +/- 0.09 for [des-(Lys(80)-Ala(81),) SNP2].