In the early, online edition of the Proceedings of the National Academy of Sciences, researchers from the US and Israel describe transcriptional read-through patterns associated with heat shock, osmotic stress, or oxidative stress in a mouse fibroblast cell line. Using RNA sequencing, the team mapped so-called "downstream of gene-containing," or DoG, transcripts under these cell stress conditions, uncovering evidence of differential transcriptional read-through induction and distinct chromatin signatures associated with the regions that produce DoGs under stressful conditions. "[I]nduction of transcriptional read-through is a hallmark of the mammalian stress response," they report, pointing to "potential roles for this class of transcripts in the maintenance of open chromatin under stress."
A Stony Brook University-led team characterizes a collection of recoded polioviruses containing as many as 2,1004 randomly scrambled codons containing synonymous mutations, considering the relationships between poliovirus genome sequences, RNA genome packaging, infectivity, proliferation, growth features and more. The researchers note that their results failed to support the notion that the packaging of polioviruses and other single-stranded RNA viruses is determined via loosely conserved hairpin sequences. Instead, they put forth a two-step assembly model for single-stranded RNA virus assembly based on the synthetic poliovirus patterns identified.
Finally, researchers from the Chinese Academy of Sciences and other centers in China present evidence for a genome stability role for the epigenetic regulator CTCF. Based on cellular and cytogenetic patterns detected in B-cell leukemia cells with depleted CTCF levels — including chromosome breaks, end fusions, and ATM kinase activation — the team suggests that the protein makes direct contributions to genome stability by contributing to double-strand DNA break repair processes. "CTCF maintains genome stability by participating in DNA repair," the authors write, "highlighting a potential link between genome organization and genome stability."