Vitellin-binding proteins in the nematode Oscheius tipulae (Nematoda, Rhabditida).
We describe the first application of a non-radioactive ligand-blotting technique to the characterization of proteins interacting with nematode vitellins. Chromatographically purified vitellins from the free-living nematode Oscheius tipulae were labeled with fluorescein in vitro. Ligand-blotting assays with horseradish peroxidase-conjugated anti-fluorescein antibodies showed that labeled vitellins reacted specifically with a polypeptide of approximately 100 kDa, which we named P100. This polypeptide is a specific worm's vitellin-binding protein that is present only in adult worms. Blots containing purified O. tipulae vitellin preparations showed no detectable signal in the 100 kDa region, ruling out any possibility of yolk polypeptides self-assembling under the conditions used in our assay. Experiments done in the presence of alpha-methyl mannoside ruled out the possibility of vitellins binding to P100 through mannose residues. Triton X-114 fractionation of whole worm extracts showed that P100 is either a membrane protein or has highly hydrophobic regions.
Serino
João Carlos
JC
Department of Parasitology, Instituto de Ciências Biomédicas - Universidade de São Paulo, Av. Prof. Lineu Prestes, 1374, 05508-900 São Paulo - SP, Brazil.
Almenara
Daniela Peres
DP
Penha-Scarabotto
Cristiane
C
de Moura
Joselene Pereira
JP
Winter
Carlos Eduardo
CE
D000818:Animals; D011485:Protein Binding; D017168:Rhabditida / Q000378:metabolism*; D047048:Vitellins / Q000378:metabolism*
D047048:Vitellins