Isolation and characterisation of a cDNA encoding a zona pellucida protein (ZPB) from the marsupial Trichosurus vulpecula (brushtail possum).
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.
Haines
B P
BP
Department of Biochemistry, University of Adelaide, South Australia.
Rathjen
P D
PD
Hope
R M
RM
Whyatt
L M
LM
Holland
M K
MK
Breed
W G
WG
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
D018076:DNA, Complementary; D004527:Egg Proteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins