title: Isolation and characterisation of a cDNA encoding a zona pellucida protein (ZPB) from the marsupial Trichosurus vulpecula (brushtail possum).
abstract: We have cloned a cDNA containing the entire coding sequence of a marsupial (the brushtail possum, Trichosurus vulpecula) zona pellucida protein (ZPB). The open reading frame of 1,581 nt is predicted to encode a ZPB polypeptide of 527 amino acids which contains 20 cysteine residues, 7 potential N-linked glycosylation sites, a potential N-terminal signal peptide and a potential C-terminal trans-membrane domain, preceded by a furin proteolytic processing signal. Sequence comparisons between possum ZPB and orthologous polypeptides from 7 eutherian species and from Xenopus laevis, reveal the existence of a high degree of sequence similarity, particularly in the central portion of the molecule. Cysteine residues are highly conserved, and all nine species possess potential N-terminal signal peptide sequences and C-terminal trans-membrane domains of approximately the same length. In situ hybridisation revealed that expression of ZPB was restricted to oocytes of primordial and primary follicles of adult possums; no expression was detected in the surrounding granulosa cells. The broad conservation of ZPB sequence, structure and expression over a wide range of mammalian species, revealed by our studies, makes it unlikely that these features account for the different properties of the marsupial and eutherian zona pellucidae.
authors.affiliation: Department of Biochemistry, University of Adelaide, South Australia.
authors.forename: B P
authors.initials: BP
authors.lastname: Haines
authors.forename: P D
authors.initials: PD
authors.lastname: Rathjen
authors.forename: R M
authors.initials: RM
authors.lastname: Hope
authors.forename: L M
authors.initials: LM
authors.lastname: Whyatt
authors.forename: M K
authors.initials: MK
authors.lastname: Holland
authors.forename: W G
authors.initials: WG
authors.lastname: Breed
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary; D004527:Egg Proteins / Q000235:genetics* / Q000302:isolation & purification; D015870:Gene Expression; D006801:Humans; D008394:Marsupialia / Q000235:genetics*; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D011956:Receptors, Cell Surface; D017386:Sequence Homology, Amino Acid; D000072216:Zona Pellucida Glycoproteins
chemical_list: D018076:DNA, Complementary; D004527:Egg Proteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins