ABSTRACT
Sigma factor σ(54) has a distinct modus operandi for mediating the activation of bacterial RNA polymerase (RNAP) at promoter recognition motifs 12 and 24 bp upstream from transcription start sites. σ(54) was thought to act as monomer in all transcription steps. However, we provide evidence that σ(54) of Pseudomonas putida interacts stably with itself. The interface between monomers involves contacts in σ(54) regions I and III, sequences that play key roles in the transcription activation of σ(54)-RNAP holoenzyme. These roles include interactions with activator proteins and the -12 and -24 motifs. In particular, we detected inter-monomer contacts between region I, and between region I and the C-terminal portion of region III. Our results suggest a new auto-antagonistic regulatory state of σ(54).
Subject(s)
Pseudomonas putida/metabolism , RNA Polymerase Sigma 54/metabolism , Transcription, Genetic , Protein Multimerization , RNA Polymerase Sigma 54/chemistry , RNA, Bacterial/metabolism , Transcriptional Activation , Two-Hybrid System TechniquesABSTRACT
Trimethylation of Lys36 in histone H3 (H3K36me3) coordinates events associated with the elongation phase of transcription and is also emerging as an important epigenetic regulator of cell growth and differentiation. We have identified the PWWP domain of bromo and plant homeodomain (PHD) finger-containing protein 1 (BRPF1) as a H3K36me3 binding module and have determined the structure of this domain in complex with an H3K36me3-derived peptide.
