title: The P25 component of Galleria silk.
abstract: The water-insoluble core of lepidopteran silk is composed of four major proteins, but only three genes have been identified. This study demonstrates that the 29- and 30-kDa components of Galleria mellonella silk are derived from a single gene designated P25. The gene is expressed exclusively in the posterior section of the silk glands as a 2-kb mRNA, which accumulates in the feeding larvae and declines at molting. The mRNA encodes a peptide of 24,864 Da that exhibits 51% identity with the putative product of the P25 gene of Bombyx. The conservation of several amino acid stretches, including the relative positions of all 8 cysteines in the mature polypeptide, implies that the P25 proteins play similar, and apparently significant roles in silk formation in the two species. A Galleria P25 cDNA yields a peptide of about 25 kDa when translated in vitro; the 29- and 30-kDa forms present in the silk are derived from this primary translation product by differential glycosylation.
authors.affiliation: Institute of Entomology, Academy of Sciences, and Faculty of Biological Sciences, University of South Bohemia, Ceské Budejovice, Czech Republic.
authors.forename: M
authors.initials: M
authors.lastname: Zurovec
authors.forename: D
authors.initials: D
authors.lastname: Kodrík
authors.forename: C
authors.initials: C
authors.lastname: Yang
authors.forename: F
authors.initials: F
authors.lastname: Sehnal
authors.forename: K
authors.initials: K
authors.lastname: Scheller
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D012831:Bombyx / Q000235:genetics; D005349:Fibroins / Q000235:genetics; D017344:Genes, Insect / Q000235:genetics*; D006023:Glycoproteins / Q000235:genetics* / Q000302:isolation & purification*; D019476:Insect Proteins / Q000235:genetics*; D007915:Lepidoptera / Q000235:genetics*; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D006023:Glycoproteins; D019476:Insect Proteins; C111320:P25 protein, Galleria mellonella; D005349:Fibroins