Mutations in the human telomerase reverse transcriptase (TERT) promoter are the most frequent non-coding mutations in cancer, but their molecular mechanism in tumorigenesis has not been established. We used genome editing of human pluripotent stem cells with physiological telomerase expression to elucidate the mechanism by which these mutations contribute to human disease. Surprisingly, telomerase-expressing embryonic stem cells engineered to carry any of the three most frequent TERT promoter mutations showed only a modest increase in TERT transcription with no impact on telomerase activity. However, upon differentiation into somatic cells, which normally silence telomerase, cells with TERT promoter mutations failed to silence TERT expression, resulting in increased telomerase activity and aberrantly long telomeres. Thus, TERT promoter mutations are sufficient to overcome the proliferative barrier imposed by telomere shortening without additional tumor-selected mutations. These data establish that TERT promoter mutations can promote immortalization and tumorigenesis of incipient cancer cells.DOI:
http://dx.doi.org/10.7554/eLife.07918.001
Allergic rhinitis (AR; also nasal allergies or "hay fever") is a chronic upper airway inflammatory disease that affects ∼60 million adults and children in the United States. The duration and severity of AR symptoms contribute to a substantial burden on patients' quality of life (QoL), sleep, work productivity, and activity. This study was designed to examine symptoms, QoL, productivity, comorbidities, disease management, and pharmacologic treatment of AR in United States and ex-U.S. sufferers. Allergies in America was a comprehensive telephone-based survey of 2500 adults with AR. These data are compared and contrasted with findings from the Pediatric Allergies in America, Allergies in Latin America, and Allergies in Asia-Pacific telephone surveys. The prevalence of physician-diagnosed AR was 14% in U.S. adults, 7% in Latin America adults, and 9% in Asia-Pacific adults. Nasal congestion is the most common and bothersome symptom for adults. Approximately two-thirds of adults rely on medication to relieve intolerable AR symptoms. Incomplete relief, slow onset, <24-hour relief, and reduced efficacy with sustained use were commonly reported with AR medications, including intranasal corticosteroids. One in seven U.S. adults reported achieving little to no relief with AR medications. Bothersome adverse effects of AR medications included drowsiness, a drying feeling, medication dripping down the throat, and bad taste. Perception of inadequate efficacy was the leading cause of medication discontinuation or change and contributed to treatment dissatisfaction. These findings support the assertion that AR burden has been substantially underestimated and identify several important challenges to successful management of AR.
Aberrant complex formation by recurrent interaction modules, such as BTB domains, leucine zippers, or coiled coils, can disrupt signal transduction, yet whether cells detect and eliminate complexes of irregular composition is unknown. By searching for regulators of the BTB family, we discovered a quality control pathway that ensures functional dimerization [dimerization quality control (DQC)]. Key to this network is the E3 ligase SCF, which selectively binds and ubiquitylates BTB dimers of aberrant composition to trigger their clearance by proteasomal degradation. Underscoring the physiological importance of DQC, SCF is required for the differentiation, function, and survival of neural crest and neuronal cells. We conclude that metazoan organisms actively monitor BTB dimerization, and we predict that distinct E3 ligases similarly control complex formation by other recurrent domains.
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