Pores of annulate lamellae and nuclei bind wheat germ agglutinin and monoclonal antibody similarly

Abstract

Both a monoclonal antibody against rat liver nuclear pore complex proteins and a wheat germ agglutinin (WGA) bind to the pore regions of nuclear envelopes and annulate lamellae from extracts of P3J, a cultured cell line derived from ascites of a Burkitt's lymphoma. In this system it is possible to induce large numbers of annulate lamellae whose functions are unknown but may include providing a source of nuclear envelopes. The antibody and the lectin bind fibrous material at pore margins on both sides of the nuclear envelope and cisternae of the annulate lamellae. Treating extracts of PU cells with protease removes the fibrous material from pore regions and prevents binding by WGA. Extracts treated with RNAse still possess fibrous material at the pore regions of both organelles that binds WGA. The similarity of the binding of the two types of pores and the specificity of binding argue that annulate lamellae may be a reserve form of nuclear envelopes. Binding of WGA is prevented by preincubating the extracts in N-acetylglucosamine or N,N,N-triacetylchitotriose, suggesting that both pore complexes include one or more N-acetylglucosamine-containing proteins.