Binding of vitellogenin to membranes isolated from mosquito ovaries

✍ Scribed by Tarlochan S. Dhadialla; Alexander S. Raikhel

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 1002 KB
• Volume: 18
• Category: Article
• ISSN: 0739-4462
• DOI: 10.1002/arch.940180106

✦ Synopsis

The presence of specific receptors for vitellogenin (Vg) in ovary membranes of the mosquito, Aedes aegypti, was demonstrated by an in vitro binding assay.

The binding reaction, which is dependent on p H and Ca", uses 4 pg membrane protein, 35S-Vg labeled metabolically by fat body culture in vitro, and unlabeled vitellin (Vn) for competition. At p H 7.0 and in the presence of 5 m M Ca2+, the binding of Vg t o its receptor reaches equilibrium within 60-90 min at both 4 and 25°C. The binding is specific to membranes prepared only from ovaries. While mosquito Vg and Vn bind with equal affinity to Vg receptors on ovary membranes, neither locust Vg nor mouse IgG has any measurable affinity towards these sites. Nonlinear least square analysis of the saturation isotherms i s consistent with the presence of a single class of Vg receptors on ovary membranes with a dissociation constant (Kd) of 0.18 pM