Molecular basis of microhomology-mediated end-joining by purified full-length Polθ

DNA polymerase θ (Polθ) is a unique polymerase-helicase fusion protein that promotes microhomology-mediated end-joining (MMEJ) of DNA double-strand breaks (DSBs). How full-length human Polθ performs MMEJ at the molecular level remains unknown. Using a biochemical approach, we find that the helicase is essential for Polθ MMEJ of long ssDNA overhangs which model resected DSBs. Remarkably, Polθ MMEJ of ssDNA overhangs requires polymerase-helicase attachment, but not the disordered central domain, and occurs independently of helicase ATPase activity. Using single-particle microscopy and biophysical methods, we find that polymerase-helicase attachment promotes multimeric gel-like Polθ complexes that facilitate DNA accumulation, DNA synapsis, and MMEJ. We further find that the central domain regulates Polθ multimerization and governs its DNA substrate requirements for MMEJ. These studies identify unexpected functions for the helicase and central domain and demonstrate the importance of polymerase-helicase tethering in MMEJ and the structural organization of Polθ

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

Publisher Correction: Molecular basis of microhomology-mediated end-joining by purified full-length Polθ (Nature Communications, (2019), 10, 1, (4423), 10.1038/s41467-019-12272-9)

The original version of this Article contained errors in Figure 6. In panel o, the labels incorrectly stated ‘Poleθ’ and “Poleθ + DNA” and should be labelled “Polθ” and “Polθ + DNA”. In the result section, in the sub-section entitled “Polθ Promotes MMEJ of Long ssDNA”, the sentence “Importantly, the ability of Polθ- pol to perform MMEJ on short (≤12 nt) ssDNA (Fig. 1p, left; Supplementary Fig. 3D and 3E), and short (≤15 nt) overhangs, demonstrates it performs interstrand pairing without Polθ-hel”. should read as follow: “Importantly, the ability of Polθ-pol to perform MMEJ on short (≤12 nt) ssDNA (Fig. 1p, left; Supplementary Fig. 3D and 3E), and short (≤15 nt) overhangs, demonstrates that it performs interstrand pairing without Polθ-hel”. In the sub-section entitled “Preventing Intrastrand Pairing Stimulates MMEJ by Polθ-Pol”, the sentence “We predicted that preventing base-pairing opportunities between 3' terminal bases and bases upstream along long the 5' region of long ssDNA substrates would suppress intrastrand pairing and enable interstrand pairing by Polθ-pol (Fig. 3c)”. should read as follows: “We predicted that preventing base-pairing opportunities between 3' terminal bases and bases upstream along the 5' region of long ssDNA substrates would suppress intrastrand pairing and enable interstrand pairing by Polθ-pol (Fig. 3c)”. In the method section, in the “Proteins” sub-section the sentence “Polθ-pol, Polθ-hel and RPA were purified as described”. should read as follows: “Polθ-pol and Polθ-hel were purified as described”. These corrections have now been included in the HTML and pdf of the article. Additionally, a technical problem during the publication process resulted in loss of image quality in Figs. 1, 3 and 4. This has now been corrected in both the PDF and HTML versions of the Article