title: Aplysia capsulin is localized to egg capsules and egg cordon sheaths and shares sequence homology with Drosophila dec-1 gene products.
abstract: Differential library screening of an albumen gland cDNA library, Western blot analysis, protein expression, immunolocalization studies, comparative genomics, and secretion assays identified a major Aplysia californica albumen gland protein ('capsulin') that is localized to egg capsules and to the sheaths of the egg cordon. Capsulin shared sequence homology with eggshell proteins encoded by the Drosophila dec-1 gene. The 1790-amino acid A. californica precursor contains 17 repeat sequences that are flanked by basic residue processing sites. The numerous proteolytic processing sites may facilitate the breakdown of capsulin prior to when veliger larvae break out of egg capsules as free-swimming larvae. An Aplysia brasiliana capsulin repeat sequence was 97% identical to its A. californica homolog. Capsulin fragments were not detected in the eluates of egg cordons, suggesting that capsulin is not a candidate water-borne pheromone precursor.
authors.affiliation: Department of Neuroscience and Cell Biology, Marine Biomedical Institute, University of Texas Medical Branch, 2.138 Medical research Building, Galveston, TX 77555-1069, USA.
authors.forename: Scott F
authors.initials: SF
authors.lastname: Cummins
authors.forename: Gregg T
authors.initials: GT
authors.lastname: Nagle
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001048:Aplysia / Q000737:chemistry* / Q000235:genetics; D001483:Base Sequence; D017931:DNA Primers; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics*; D004527:Egg Proteins / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification*; D005786:Gene Expression Regulation; D006801:Humans; D008969:Molecular Sequence Data; D010063:Ovum / Q000737:chemistry*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D017931:DNA Primers; D029721:Drosophila Proteins; D004527:Egg Proteins; C066329:dec-1 protein, Drosophila