Association between disease activity and quality of life in ulcerative colitis: Results from the CRONICA-UC study.

BACKGROUND AND AIM: In ulcerative colitis (UC), the main goals of treatment are to control disease activity and normalize health-related quality of life (HRQoL). In this study, we explored the relationship between disease activity (measured using the Simple Clinical Colitis Activity Index [SCCAI]) and patient HRQoL (measured using the EuroQoL [EQ]-5D-5L). METHODS: A total of 199 patients with UC were followed for 6 months. At months 3 and 6, patients completed an online SCCAI. Within 2 days of completing the SCCAI, patients completed an at-clinic EQ-5D-5L questionnaire and the treating gastroenterologist completed the SCCAI. RESULTS: A consistent and approximately linear relationship was identified between patient HRQoL and patient-completed and physician-completed SCCAIs. A lower SCCAI score corresponded to a higher EQ-5D-5L index value. Correlation between EQ-5D-5L index values and patient-completed online SCCAIs was moderate (ρ -0.49; P < 0.001) and similar to that between EQ-5D-5L index values and physician-completed SCCAIs (ρ -0.53; P < 0.001). A decrease in the EQ-5D-5L index was already observed at an SCCAI score of 2, commonly regarded as remission. A 1-point increase in the patient SCCAI corresponded to an average change of -0.027 (standard deviation, -0.032 to -0.022) in the EQ-5D-5L index, whereas a 1-point increase in the physician SCCAI corresponded to an average change of -0.030 (standard deviation, -0.036 to -0.025). CONCLUSIONS: Health-related quality of life measured using the EQ-5D-5L questionnaire is proportionally related to disease activity in patients with UC. In line with the treat-to-target objective in UC, complete control of all symptoms is required to achieve optimal improvement in patient HRQoL.

Cryo-electron microscopy studies of human TFIID: conformational breathing in the integration of gene regulatory cues.

The multisubunit transcription factor TFIID is essential for directing eukaryotic promoter recognition and mediating interactions with activators/cofactors during assembly of the preinitiation complex. Despite its central role in transcription initiation and regulation, structural knowledge of the TFIID complex has so far been largely limited to electron microscopy studies of negatively stained samples. Here, we present a cryo-electron microscopy 3D reconstruction of the large endogenous human TFIID complex. The improved cryopreservation has allowed for a more detailed definition of the structural elements in the complex and for the detection, by an extensive statistical analysis of the data, of a conformational opening and closing of the cavity central to the TFIID architecture. We propose that these density rearrangements in the structure are a likely reflection of the plasticity of the interactions between TFIID and its many partner proteins.

Recognition of RNA polymerase II and transcription bubbles by XPG, CSB, and TFIIH: insights for transcription-coupled repair and Cockayne Syndrome.

Loss of a nonenzymatic function of XPG results in defective transcription-coupled repair (TCR), Cockayne syndrome (CS), and early death, but the molecular basis for these phenotypes is unknown. Mutation of CSB, CSA, or the TFIIH helicases XPB and XPD can also cause defective TCR and CS. We show that XPG interacts with elongating RNA polymerase II (RNAPII) in the cell and binds stalled RNAPII ternary complexes in vitro both independently and cooperatively with CSB. XPG binds transcription-sized DNA bubbles through two domains not required for incision and functionally interacts with CSB on these bubbles to stimulate its ATPase activity. Bound RNAPII blocks bubble incision by XPG, but an ATP hydrolysis-dependent process involving TFIIH creates access to the junction, allowing incision. Together, these results implicate coordinated recognition of stalled transcription by XPG and CSB in TCR initiation and suggest that TFIIH-dependent remodeling of stalled RNAPII without release may be sufficient to allow repair.

RBP38, a novel RNA-binding protein from trypanosomatid mitochondria, modulates RNA stability.

We describe here the isolation and characterization of a novel RNA-binding protein, RBP38, from Leishmania tarentolae mitochondria. This protein does not contain any known RNA-binding motifs and is highly conserved among the trypanosomatids, but no homologues were found in other organisms. Recombinant LtRBP38 binds single and double-stranded (ds) RNA substrates with dissociation constants in the 100 nM range, as determined by fluorescence polarization analysis. Downregulation of expression of the homologous gene, TbRBP38, in procyclic Trypanosoma brucei by using conditional dsRNA interference resulted in 80% reduction of steady-state levels of RNAs transcribed from both maxicircle and minicircle DNA. In organello pulse-chase labeling experiments were used to determine the stability of RNAs in mitochondria that were depleted of TbRBP38. The half-life of metabolically labeled RNA decreased from approximately 160 to approximately 60 min after depletion. In contrast, there was no change in transcriptional activity. These observations suggest a role of RBP38 in stabilizing mitochondrial RNA.

Trypanosome mitochondrial 3' terminal uridylyl transferase (TUTase): the key enzyme in U-insertion/deletion RNA editing.

A 3' terminal RNA uridylyltransferase was purified from mitochondria of Leishmania tarentolae and the gene cloned and expressed from this species and from Trypanosoma brucei. The enzyme is specific for 3' U-addition in the presence of Mg(2+). TUTase is present in vivo in at least two stable configurations: one contains a approximately 500 kDa TUTase oligomer and the other a approximately 700 kDa TUTase complex. Anti-TUTase antiserum specifically coprecipitates a small portion of the p45 and p50 RNA ligases and approximately 40% of the guide RNAs. Inhibition of TUTase expression in procyclic T. brucei by RNAi downregulates RNA editing and appears to affect parasite viability.