MONOCLONAL-ANTIBODIES AGAINST EUKARYOTIC RIBOSOMES - USE TO CHARACTERIZE A RIBOSOMAL-PROTEIN NOT PREVIOUSLY IDENTIFIED AND ANTIGENICALLY RELATED TO THE ACIDIC PHOSPHOPROTEINS P1/P2

  • 1 January 1982
    • journal article
    • research article
    • Vol. 257  (21) , 2709-2715
Abstract
Mice were immunized against chick ribosomes with the use of various protocols and immunogen preparations. Hybridomas were prepared, clones screened and specific antibodies identified by reversible protein staining followed by immunoperoxidase staining on nitrocellulose blots. Clones were obtained which secreted specific antibodies against ribosomal proteins S6, L7, L18a, P1/P2 and also against rRNA. Antibodies were typed by means of a dot-binding assay with typing antibodies immobilized on a solid support of nitrocellulose, and also characterized by their species cross-reactivities. The common determinant on proteins P1 and P2 cross-reacted with proteins of similar MW in all eukaryotes tested, and with a determinant in a previously uncharacterized 38,000-dalton protein of the large ribosomal subunit. This protein was designated P0. The determinant of P0 was also present in a protein of similar MW in all eukaryotes tested. Unlike P1 and P2, P0 was not removable from ribosomes by an ethanol-NH4Cl washing procedure. No evidence for a precursor-product relationship between P0 and P1/P2 was found. P0, P1 and P2 were found in active polysomes and in the nucleolus. The MW of the nucleolar forms were not identical with those of the cytoplasmic forms, suggesting some processing during ribosomal assembly and/or transport.