Snapshots of the RNA processing factor SCAF8 bound to different phosphorylated forms of the carboxyl-terminal domain of RNA polymerase II.
Concomitant with RNA polymerase II (Pol II) transcription, RNA maturation factors are recruited to the carboxyl-terminal domain (CTD) of Pol II, whose phosphorylation state changes during a transcription cycle. CTD phosphorylation triggers recruitment of functionally different factors involved in RNA processing and transcription termination; most of these factors harbor a conserved CTD interacting domain (CID). Orchestration of factor recruitment is believed to be conducted by CID recognition of distinct phosphorylated forms of the CTD. We show that the human RNA processing factor SCAF8 interacts weakly with the unphosphorylated CTD of Pol II. Upon phosphorylation, affinity for the CTD is increased; however, SCAF8 is promiscuous to the phosphorylation pattern on the CTD. Employing a combined structural and biophysical approach, we were able to distinguish motifs within CIDs that are involved in a generic CTD sequence recognition from items that confer phospho-specificity.
Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany.
Roland
R
Becker
Bernhard
B
Loll
Anton
A
Meinhart
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D006801:Humans; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D012319:RNA Polymerase II / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional / Q000502:physiology*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic; D014961:X-Ray Diffraction
D010446:Peptide Fragments; D016601:RNA-Binding Proteins; C531982:SCAF8 protein, human; D012319:RNA Polymerase II