No abstract

We have developed a simple and rapid method for isolation of purified nuclear lamina from Ehrlich ascites tumor cells. The procedure employs chromatin structures prepared from whole cells at low ionic strength and is carried out under conditions that minimize the formation of artifactual protein-DNA complexes. When the isolation is performed in the presence of EDTA, nuclear lamina without distinct pore complexes is obtained. In the absence of EDTA, intact pore complexes and a large amount of vimentin 100 A filaments are seen associated with nuclear lamina. The main nuclear lamina proteins are characterized using gel electrophoresis, immunoblotting, and two-dimensional peptide mapping. An extensive structural homology is found between lamin A and lamin C, whose peptide maps differ by only one major spot, whereas lamin B has apparently unrelated pattern.

No abstract

Batches of osmium-ammine (OA) complex vary considerably in staining properties when used in a Feulgen-like reaction for selective staining of DNA-containing structures. An alternative procedure for preparation of Schiff-like reagent from OA complex is described. It is based on generation of H2SO3, respectively SO2, within the OA solution and ensures more favorable conditions for production of a Schiff-like stain than bubbling with SO2 does. The method is reproducible and yields high staining intensity. Data obtained suggest that the ability of OA complex to produce Feulgen-like staining is strongly influenced by variations in its chemical composition. Their unfavorable effect can be overcome by selecting suitable conditions for preparation of a Schiff-like reagent. Conditions for obtaining specific and sensitive Feulgen-like staining are determined.

No abstract