A novel osteopontin-like protein is expressed in the trout ovary during ovulation

Using suppression subtraction hybridization between ovulatory and postovula tory trout ovaries, a down-regulated cDNA was obtained that presumably enco des a novel ovarian protein ('NOP'), NOP mRNA is present in the ovary durin g ovulation and down-regulated by 48 h postovulation, suggesting an importa nt role for NOP during ovulation, Besides the ovary, NOP is also strongly e xpressed in the testis and at lower levels in the skin, gills, kidney and g astrointestinal tract. While the overall identity is not high, NOP shares s everal sequence similarities with mammalian and chicken osteopontins, inclu ding the percentage of aspartate, serine and alanine residues and the prese nce of a cell attachment motif, (C) 2001 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.