A full length cDNA clone was isolated by screening a mixed stage Globodera
pallida expression library using the monospecific polyclonal antibody
IACR-PC320. Sequence comparison indicated that the predicted 332 amino acid
protein encoded by the cDNA was a member of the annexin gene family named
gp-nex and very similar to annexins found in other nematode species.
Annexins are calcium-dependent phospholipid binding proteins characterised
by four repeated domains approximately 70 amino acids in length. The
predicted amino acid sequence of the protein did not contain an N-terminal
secretion signal peptide; however, the protein was shown to be present in
excretory/secretory products from G. pallida second stage juveniles treated
with the neurotransmitter 5 methoxy-N, N dimethyl tryptamine. Gp-nex encodes
a protein of 35 kDa and was immunolocalised in the amphids, genital
primordium and in the constraining muscles above and below the metacorpus
pump chamber of G. pallida second stage juveniles. It is also present in
eggs and adult females of the two species of the potato cyst nematodes.