The mechanism of DNA unwinding by the eukaryotic replicative helicase

Accurate DNA replication is tightly regulated in eukaryotes to ensure genome stability during cell division and is performed by the multi-protein replisome. At the core an AAA+ hetero-hexameric complex, Mcm2-7, together with GINS and Cdc45 form the active replicative helicase Cdc45/Mcm2-7/GINS (CMG). It is not clear how this replicative ring helicase translocates on, and unwinds, DNA. We measure real-time dynamics of purified recombinant Drosophila melanogaster CMG unwinding DNA with single-molecule magnetic tweezers. Our data demonstrates that CMG exhibits a biased random walk, not the expected unidirectional motion. Through building a kinetic model we find CMG may enter up to three paused states rather than unwinding, and should these be prevented, in vivo fork rates would be recovered in vitro. We propose a mechanism in which CMG couples ATP hydrolysis to unwinding by acting as a lazy Brownian ratchet, thus providing quantitative understanding of the central process in eukaryotic DNA replication

Quality of Life Is Impaired in Men with Chronic Prostatitis: The Chronic Prostatitis Collaborative Research Network

OBJECTIVE: Health-related quality of life (HRQOL) impairment may be a central component of chronic prostatitis for men afflicted with this condition. Our objective was to examine HRQOL, and factors associated with HRQOL, using both general and condition-specific instruments. DESIGN: Chronic Prostatitis Cohort (CPC) study. SETTING: Six clinical research centers across the United States and Canada. PARTICIPANTS: Two hundred seventy-eight men with chronic prostatitis. MEASUREMENTS AND MAIN RESULTS: The Short Form 12 (SF-12) Mental Component Summary (MCS) and Physical Component Summary (PCS), and the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) were measures used. CPC subjects' MCS scores (44.0 ± 9.8) were lower than those observed in the most severe subgroups of patients with congestive heart failure and diabetes mellitus, and PCS scores (46.4±9.5) were worse than those among the general U.S. male population. Decreasing scores were seen in both domains with worsening symptom severity (P< .01). History of psychiatric disease and younger age were strongly associated with worse MCS scores, whereas history of rheumatologic disease was associated with worse PCS scores. Predictors of more severe NIH-CPSI scores included lower educational level and lower income; history of rheumatic disease was associated with higher scores. CONCLUSIONS: Men with chronic prostatitis experience impairment in the mental and physical domains of general HRQOL, as well as condition-specific HRQOL. To optimize the care of men with this condition, clinicians should consider administering HRQOL instruments to their patients to better understand the impact of the condition on patients' lives

Histone H3.3G34-Mutant Interneuron Progenitors Co-opt PDGFRA for Gliomagenesis

Histone H3.3 glycine 34 to arginine/valine (G34R/V) mutations drive deadly gliomas and show exquisite regional and temporal specificity, suggesting a developmental context permissive to their effects. Here we show that 50% of G34R/V tumors (n = 95) bear activating PDGFRA mutations that display strong selection pressure at recurrence. Although considered gliomas, G34R/V tumors actually arise in GSX2/DLX-expressing interneuron progenitors, where G34R/V mutations impair neuronal differentiation. The lineage of origin may facilitate PDGFRA co-option through a chromatin loop connecting PDGFRA to GSX2 regulatory elements, promoting PDGFRA overexpression and mutation. At the single-cell level, G34R/V tumors harbor dual neuronal/astroglial identity and lack oligodendroglial programs, actively repressed by GSX2/DLX-mediated cell fate specification. G34R/V may become dispensable for tumor maintenance, whereas mutant-PDGFRA is potently oncogenic. Collectively, our results open novel research avenues in deadly tumors. G34R/V gliomas are neuronal malignancies where interneuron progenitors are stalled in differentiation by G34R/V mutations and malignant gliogenesis is promoted by co-option of a potentially targetable pathway, PDGFRA signaling