Affinity of animal cell nucleoli for normal serum. Preliminary characterization of serum and cell components.
Nucleoli of animal cells cultured in vitro are modified by a component of "nonimmune" animal serum. Modified nucleoli bind fluorescein-conjugated nonimmune serum proteins, as shown by calcium ion-dependent fluorescence. Analysis of serum indicates that the nucleolar-binding component is a globulin, with an electrophoretic mobility in the same region as the slow alpha-1 component in pH 8.6 Veronal buffer. The component has a low sedimentation constant (2.4S), and appears to contain glycoprotein with relatively high sialic acid content (8.5%); the latter moiety may be essential to reaction with nucleoli. The nucleolar component reacting with this alpha globulin fraction appears to be a histonelike basic protein. Primary cultures of animal cells have been supported for 1 wk through attachment, spreading, and outgrowth from colonies to confluent monolayers in medium containing a nucleolar-reactive serum fraction as the only protein supplement.
D000510:Alpha-Globulins / Q000494:pharmacology*; D000818:Animals; D001774:Blood Chemical Analysis; D001797:Blood Protein Electrophoresis; D001798:Blood Proteins / Q000494:pharmacology*; D002466:Cell Nucleolus / Q000187:drug effects*; D046508:Culture Techniques; D005453:Fluorescence; D006023:Glycoproteins / Q000494:pharmacology*; D000882:Haplorhini; D006651:Histocytochemistry; D006801:Humans; D007668:Kidney / Q000254:growth & development; D008854:Microscopy, Electron; D014461:Ultracentrifugation
D000510:Alpha-Globulins; D001798:Blood Proteins; D006023:Glycoproteins