Interactions between the human RNA polymerase II subunits.
As an initial approach to characterizing the molecular structure of the human RNA polymerase II (hRPB), we systematically investigated the protein-protein contacts that the subunits of this enzyme may establish with each other. To this end, we applied a glutathione S-transferase-pulldown assay to extracts from Sf9 insect cells, which were coinfected with all possible combinations of recombinant baculoviruses expressing hRPB subunits, either as untagged polypeptides or as glutathione S-transferase fusion proteins. This is the first comprehensive study of interactions between eukaryotic RNA polymerase subunits; among the 116 combinations of hRPB subunits tested, 56 showed significant to strong interactions, whereas 60 were negative. Within the intricate network of interactions, subunits hRPB3 and hRPB5 play a central role in polymerase organization. These subunits, which are able to homodimerize and to interact, may constitute the nucleation center for polymerase assembly, by providing a large interface to most of the other subunits.
Acker
J
J
Institut de Génétique et de Biologie Moléculaire et Cellulaire (CNRS/INSERM/ULP), F-67404 Illkirch Cedex C.U. de Strasbourg, France.
de Graaff
M
M
Cheynel
I
I
Khazak
V
V
Kedinger
C
C
Vigneron
M
M
D016367:Baculoviridae; D003001:Cloning, Molecular; D003545:Cysteine / Q000032:analysis; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D008715:Methionine / Q000032:analysis; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D012319:RNA Polymerase II / Q000737:chemistry* / Q000235:genetics
D008715:Methionine; D012319:RNA Polymerase II; D005978:Glutathione; D003545:Cysteine