In the early, online edition of the Proceedings of the National Academy of Sciences, researchers from the University of California, San Francisco, and elsewhere demonstrate the feasibility of adding in or removing specific sequences in human immune CD4+ T cells using a CRISPR/Cas9 gene editing system. With the help of so-called Cas9 single-guide RNA ribonucleoproteins, for example, the team showed that it was possible to produce sub-populations that lacked receptors used by HIV to enter cells or by cancer cells to dodge immune recognition. GenomeWeb has more on the study, here.
A team from the US and Egypt looks at relationships between surface water phytoplankton, bacteria, and archaea in water samples from Southern Ocean sites neighboring Antarctic sea ice in McMurdo Sound. The researchers did RNA sequencing on samples collected from the Sound over time and in the presence or absence of micronutrients such as iron or cobalamin, providing a look at biosynthesis and consumption patterns in bacteria and/or archaea that support or compete with processes performed by the phytoplankton. "By identifying microbial gene expression changes in response to altered micronutrient availability, we describe the molecular underpinnings of limitation by both cobalamin and iron," researchers write, "and offer evidence that this limitation is driven by multiple phytoplankton-bacterial interactions."
Finally, investigators based in the US, Spain, and Colombia report on retrotransposons that appear to act as regulatory elements known as insulators in the human genome. By bringing genome sequence data together with functional clues — including transposable element binding patterns around chromatin domains — the team narrowed in on almost 1,200 'mammalian-wide interspersed repeats,' or MIRs, with potential insulator activity in human CD4+ T cells. After verifying and further scrutinizing a subset of the insulators computationally and experimentally, the study's authors argue that insulator MIRs may regulate chromatin domains through transcriptional complex and chromatin modifying enzyme recruitment.