In a paper published online in advance in PNAS this week, an international team led by investigators at University of Medicine and Dentistry of New Jersey shows that chronic stress promotes ionizing radiation-induced tumorigenesis in p53+/− mice. "We found that chronic restraint decreases the levels and function of p53 in mice, and furthermore, promotes the growth of human xenograft tumors in a largely p53-dependent manner," the authors write, adding that "this study demonstrates that chronic stress promotes tumorigenesis in mice, and the attenuation of p53 function is an important part of the underlying mechanism, which can be mediated by glucocortcoids elevated during chronic restraint."
Elsewhere in this week's Early Edition, researchers from the Chinese Academy of Sciences report having examined midlife hepatic gene expression in mice under different dietary conditions and, in doing so, having identified "genes and pathways that modulate the aging process." The CAS-led team reports having "found that pathways transcriptionally correlated with diet-modulated lifespan and physiological changes were enriched for lifespan-modifying genes," and that "mitochondrial gene expression correlated with lifespan and anticorrelated with aging-related pathological changes," while peroxisomal gene expression showed the opposite. Overall, the authors say that their "findings show that transcriptional changes resulting from dietary interventions can effectively reflect causal factors in aging and identify previously unknown or under-appreciated longevity pathways, such as the peroxisome pathway."
University of Bristol's Jack Davison and his colleagues identify a gene cluster encoding the biosynthesis of the fungal tropolone stipitatic acid in Talaromyces stipitatus, and investigate its function via targeted gene knockout experiments. "Comparison of the T. stipitatus tropolone biosynthetic cluster with other known gene clusters allows clarification of important steps during the biosynthesis of other fungal compounds including the xenovulenes, citrinin, sepedonin, sclerotiorin, and asperfuranone," Davison et al. write in a PNAS paper published online in advance this week.