Determinants of the SMN Tudor Domain Interaction with the RG-tail of SmD3

The Survival of Motor Neurons protein (SMN) forms the core of a large protein complex termed the ‘SMN complex’. The primary characterized function of the SMN complex is to facilitate the specific assembly of seven Sm proteins onto uridine-rich small nuclear RNAs (UsnRNAs) which function in pre-mRNA splicing. Of the three known functional domains of SMN, the Tudor domain forms the centrally-located, structured region and functions in the recognition of a subset of Sm proteins (SmD1, D3, and B) via symmetric dimethyl modification of key arginine residues (sDMA) in the RG-tails. Here, the details of this interaction are explored to understand the nature of sDMA specificity and the role of substrate regions outside of the sDMA modification. Using fluorescence polarization direct binding and competition assays and by selective modification of the SmD3 RG-tail, the factors that contribute to binding are elucidated. We find that the SMN Tudor domain requires methyl modification for interaction and prefers sDMA, but binds with only slightly reduced affinity to MMA and aDMA-modified substrate. Furthermore, μM efficient M binding affinity is achieved only in the context of the full SmD3 tail, where peptide backbone interactions and electrostatics make important contributions to binding. This feature permits the SMN Tudor domain to recognize not only SmD3, but other methylated RG-containing substrates in a similar manner. SMN is also of clinical significance; loss of function via deletion or mutation has been linked to Spinal Muscular Atrophy (SMA). SMA is an autosomal recessive neurodegenerative disease affecting neurons and leading to progressive muscle wasting. To date, 25 mutations of SMN have been identified in patients. Nearly a third (8) of these are found within the Tudor domain and roughly half (12) are located in the C-terminal oligomerization domain. This study also aims to understand the biochemical consequences of these 20 mutations in SMN. Utilizing SmD3 binding assays in conjunction with biophysical experiments to study oligomerization, several SMA patient mutations were determined to be binding deficient, oligomerization deficient, or hyper-oligomerized relative to wild-type SMN. These results provide important new insights into the molecular basis for SMN function and the biochemical basis for SMA

Determinants of the SMN Tudor Domain Interaction with the RG-tail of SmD3

The Survival of Motor Neurons protein (SMN) forms the core of a large protein complex termed the ‘SMN complex’. The primary characterized function of the SMN complex is to facilitate the specific assembly of seven Sm proteins onto uridine-rich small nuclear RNAs (UsnRNAs) which function in pre-mRNA splicing. Of the three known functional domains of SMN, the Tudor domain forms the centrally-located, structured region and functions in the recognition of a subset of Sm proteins (SmD1, D3, and B) via symmetric dimethyl modification of key arginine residues (sDMA) in the RG-tails. Here, the details of this interaction are explored to understand the nature of sDMA specificity and the role of substrate regions outside of the sDMA modification. Using fluorescence polarization direct binding and competition assays and by selective modification of the SmD3 RG-tail, the factors that contribute to binding are elucidated. We find that the SMN Tudor domain requires methyl modification for interaction and prefers sDMA, but binds with only slightly reduced affinity to MMA and aDMA-modified substrate. Furthermore, μM efficient M binding affinity is achieved only in the context of the full SmD3 tail, where peptide backbone interactions and electrostatics make important contributions to binding. This feature permits the SMN Tudor domain to recognize not only SmD3, but other methylated RG-containing substrates in a similar manner. SMN is also of clinical significance; loss of function via deletion or mutation has been linked to Spinal Muscular Atrophy (SMA). SMA is an autosomal recessive neurodegenerative disease affecting neurons and leading to progressive muscle wasting. To date, 25 mutations of SMN have been identified in patients. Nearly a third (8) of these are found within the Tudor domain and roughly half (12) are located in the C-terminal oligomerization domain. This study also aims to understand the biochemical consequences of these 20 mutations in SMN. Utilizing SmD3 binding assays in conjunction with biophysical experiments to study oligomerization, several SMA patient mutations were determined to be binding deficient, oligomerization deficient, or hyper-oligomerized relative to wild-type SMN. These results provide important new insights into the molecular basis for SMN function and the biochemical basis for SMA

Thigh-length compression stockings and DVT after stroke

Controversy exists as to whether neoadjuvant chemotherapy improves survival in patients with invasive bladder cancer, despite randomised controlled trials of more than 3000 patients. We undertook a systematic review and meta-analysis to assess the effect of such treatment on survival in patients with this disease

Proceedings of International Web Conference in Civil Engineering for a Sustainable Planet

This proceeding contains articles of the various research ideas of the academic community and practitioners accepted at the "International Web Conference in Civil Engineering for a Sustainable Planet (ICCESP 2021)". ICCESP 2021 is being Organized by the Habilete Learning Solutions, Kollam in Collaboration with American Society of Civil Engineers (ASCE), TKM College of Engineering, Kollam, and Baselios Mathews II College of Engineering, Kollam, Kerala, India. Conference Title: International Web Conference in Civil Engineering for a Sustainable PlanetConference Acronym: ICCESP 2021Conference Date: 05–06 March 2021Conference Location: Online (Virtual Mode)Conference Organizer: Habilete Learning Solutions, Kollam, Kerala, IndiaCollaborators: American Society of Civil Engineers (ASCE), TKM College of Engineering, Kollam, and Baselios Mathews II College of Engineering, Kollam, Kerala, India

Azithromycin in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Background Azithromycin has been proposed as a treatment for COVID-19 on the basis of its immunomodulatory actions. We aimed to evaluate the safety and efficacy of azithromycin in patients admitted to hospital with COVID-19. Methods In this randomised, controlled, open-label, adaptive platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), several possible treatments were compared with usual care in patients admitted to hospital with COVID-19 in the UK. The trial is underway at 176 hospitals in the UK. Eligible and consenting patients were randomly allocated to either usual standard of care alone or usual standard of care plus azithromycin 500 mg once per day by mouth or intravenously for 10 days or until discharge (or allocation to one of the other RECOVERY treatment groups). Patients were assigned via web-based simple (unstratified) randomisation with allocation concealment and were twice as likely to be randomly assigned to usual care than to any of the active treatment groups. Participants and local study staff were not masked to the allocated treatment, but all others involved in the trial were masked to the outcome data during the trial. The primary outcome was 28-day all-cause mortality, assessed in the intention-to-treat population. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936. Findings Between April 7 and Nov 27, 2020, of 16 442 patients enrolled in the RECOVERY trial, 9433 (57%) were eligible and 7763 were included in the assessment of azithromycin. The mean age of these study participants was 65·3 years (SD 15·7) and approximately a third were women (2944 [38%] of 7763). 2582 patients were randomly allocated to receive azithromycin and 5181 patients were randomly allocated to usual care alone. Overall, 561 (22%) patients allocated to azithromycin and 1162 (22%) patients allocated to usual care died within 28 days (rate ratio 0·97, 95% CI 0·87–1·07; p=0·50). No significant difference was seen in duration of hospital stay (median 10 days [IQR 5 to >28] vs 11 days [5 to >28]) or the proportion of patients discharged from hospital alive within 28 days (rate ratio 1·04, 95% CI 0·98–1·10; p=0·19). Among those not on invasive mechanical ventilation at baseline, no significant difference was seen in the proportion meeting the composite endpoint of invasive mechanical ventilation or death (risk ratio 0·95, 95% CI 0·87–1·03; p=0·24). Interpretation In patients admitted to hospital with COVID-19, azithromycin did not improve survival or other prespecified clinical outcomes. Azithromycin use in patients admitted to hospital with COVID-19 should be restricted to patients in whom there is a clear antimicrobial indication. Funding UK Research and Innovation (Medical Research Council) and National Institute of Health Research