Asymmetrical nucleosomal DNA signatures regulate transcriptional directionality.

Despite the symmetrical structure of nucleosomes, in vitro studies have shown that transcription proceeds with different efficiency depending on the orientation of the DNA sequence around them. However, it is unclear whether this functional asymmetry is present in vivo and whether it could regulate transcriptional directionality. Here, we report that the proximal and distal halves of nucleosomal DNA contribute differentially to nucleosome stability in the genome.

Design, construction, and functional characterization of a tRNA neochromosome in yeast.

Here, we report the design, construction, and characterization of a tRNA neochromosome, a designer chromosome that functions as an additional, de novo counterpart to the native complement of Saccharomyces cerevisiae. Intending to address one of the central design principles of the Sc2.0 project, the ∼190-kb tRNA neochromosome houses all 275 relocated nuclear tRNA genes.

Loss of Autonomy: Likely Dementia and Living Arrangement Transitions Among Mexicans and Mexican Americans.

Background And Objectives: To examine the role of probable dementia on changes in living arrangements and mortality among very old Mexicans and Mexican Americans in 2 different nations.

Research Design And Methods: We employ the Hispanic Established Population for the Epidemiologic Study of the Elderly and the Mexican Health and Aging Study, 2 comparable longitudinal data sets, to identify predictors of changes in living arrangements using multinomial logistic regression, controlling for cognitive status, demographic characteristics, and resources.

Results: In Mexico, women with dementia who lived alone at baseline were more likely to become part of an extended family household than men with similar levels of cognitive impairment.

A role for the Saccharomyces cerevisiae Rtt109 histone acetyltransferase in R-loop homeostasis and associated genome instability.

The stability of the genome is occasionally challenged by the formation of DNA-RNA hybrids and R-loops, which can be influenced by the chromatin context. This is mainly due to the fact that DNA-RNA hybrids hamper the progression of replication forks, leading to fork stalling and, ultimately, DNA breaks. Through a specific screening of chromatin modifiers performed in the yeast Saccharomyces cerevisiae, we have found that the Rtt109 histone acetyltransferase is involved in several steps of R-loop-metabolism and their associated genetic instability.