Volume 27 Issue 5, May 2017

In a new paper in Cell Research, Ji et al. find that transcription factor-instigated opening of chromatin, during cell reprogramming, can be sensed by the Baf60b-containing chromatin remodeling complex, which then activates the ATM-p53 pathway, leading to cell death. These findings from reprogramming studies unveil what I term a “chromatin remodeling checkpoint” whereby extensive, inappropriate chromatin opening events lead to cell elimination, thus preventing cell fate conversion that might occur upon tissue damage; if unchecked, such conversion could lead to metaplasia and cancer.

Totipotency is the ability of a single cell to form an entire embryo, including extraembryonic tissues, an ability we have yet to recapitalize, in vitro. In a recent paper published in Science, Choi et al. showed that pluripotent stem cells lacking microRNA miR-34a, have an expanded cell fate potential allowing differentiation into not only embryonic but also extraembryonic lineages.

Targeted proteolysis plays an important role in the execution and regulation of many cellular events. Two recent papers in Science identify novel roles for proteasome-mediated proteolysis in homologous chromosome pairing, recombination, and segregation during meiosis.

Long non-coding RNAs (lncRNAs) belong to the ever-increasing number of transcripts that are thought not to encode proteins. A recent study has now identified a small polypeptide encoded by the lncRNA LINC00961 that inhibits amino acid-induced mTORC1 activation in skeletal muscle.