Analysis of Schizosaccharomyces pombe Mediator reveals a set of essential subunits conserved between yeast and metazoan cells
- Henrik Spåhr*,
- Camilla O. Samuelsen†,
- Vera Baraznenok*,
- Isabelle Ernest‡,
- Danny Huylebroeck‡,
- Jacques E. Remacle‡,
- Tore Samuelsson§,
- Thomas Kieselbach*,
- Steen Holmberg†, and
- Claes M. Gustafsson*,¶
- *Department of Medical Nutrition, Karolinska Institute, Novum, S-141 86 Huddinge, Sweden; †Department of Genetics, Institute of Molecular Biology, Oester Farimagsgade 2A, DK-1353 Copenhagen K, Denmark; ‡Department of Cell Growth, Differentiation, and Development (VIB-07), Flanders Interuniversity Institute of Biotechnology (VIB), and Laboratory of Molecular Biology (CELGEN), University of Leuven, B-3000 Leuven, Belgium; and §Department of Medical Biochemistry, Göteborg University, P.O. Box 440, S-405 30 Göteborg, Sweden
-
Edited by Roger D. Kornberg, Stanford University School of Medicine, Stanford, CA, and approved July 24, 2001 (received for review May 22, 2001)
Abstract
With the identification of eight new polypeptides, we here complete the subunit characterization of the Schizosaccharomyces pombe RNA polymerase II holoenzyme. The complex contains homologs to all 10 essential gene products present in the Saccharomyces cerevisiae Mediator, but lacks clear homologs to any of the 10 S. cerevisiae components encoded by nonessential genes. S. pombe Mediator instead contains three unique components (Pmc2, -3, and -6), which lack homologs in other cell types. Presently, pmc2 + and pmc3 + have been shown to be nonessential genes. The data suggest that S. pombe and S. cerevisiae share an essential protein module, which associates with nonessential speciesspecific subunits. In support of this view, sequence analysis of the conserved yeast Mediator components Med4 and Med8 reveals sequence homology to the metazoan Mediator components Trap36 and Arc32. Therefore, 8 of 10 essential genes conserved between S. pombe and S. cerevisiae also have a metazoan homolog, indicating that an evolutionary conserved Mediator core is present in all eukaryotic cells. Our data suggest a closer functional relationship between yeast and metazoan Mediator than previously anticipated.
Footnotes
-
↵ ¶ To whom reprint requests should be addressed. E-mail: claes.gustafsson{at}mednut.ki.se.
-
This paper was submitted directly (Track II) to the PNAS office.
- Abbreviation:
- GST,
- glutathione S-transferase
- Copyright © 2001, The National Academy of Sciences
