We have extended our immunological studies of yeast nuclear RNA polymerases (BuhlerJ, . M., Huet, J., Davies, K., Sentenac, A., and Fromageot, P. (1980) J. Biol. Chem 255, 9949-9954) and explored the immunological relationships of form B RNA polymerase from yeast, plant, insect, crustacea, and mammal. The three forms of RNA polymerases from Saccharomyces cerevisiae were spotted on nitrocellulose filters and then probed with specific antibodies directed against each polypeptide component of yeast RNA polymerase A or B. The subunit-IgG complexes were detected by 125I-labeled Protein A. This spot-immunodetection method revealed clearly the polypeptides common to enzymes A and C (AC4O and AC19) as well as the core of common subunits (ABC27, ABC23, and ABC14.5). A small cross-reaction was also observed between the three enzymes with the antibodies to the large polypeptides enzyme A or B. RNA polymerase B from wheat germ, Artemia salina, Drosophila melanogaster, and calf thymus cross-reacted strongly with antibodies to the largest subunit of yeast Enzyme B (B220 or B185) and to a lesser extent with anti-B150 IgG. A small cross-reaction was observed with antibodies to the large subunits of the yeast enzyme A (A190 and A135). All of the enzymes also shared a few immunological determinants with one of the common polypeptides of the yeast enzymes (ABC23). In addition to these general cross-reactions, some specific antibodies reacted with wheat germ enzyme B or the Drosophila enzyme. None of the antibodies reacted with Escherichia coli RNA polymerase. The results illustrate the structural evolution of eukaryotic RNA polymerases at the subunit level.

• PMID: 6174508
• PubMed

Reference Type

Comparative Study | Journal Article

Authors

Huet J, Sentenac A, Fromageot P

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