In Cell Stem Cell this week, researchers at the University of Pennsylvania and Children's Hospital of Philadelphia present a "highly efficient" microRNA-mediated method to reprogram mouse and human somatic cells to pluripotency. The team reports that the "miR302/367 cluster rapidly and efficiently reprograms mouse and human somatic cells to an iPSC state without a requirement for exogenous transcription factors," and thus facilitates a "reprogramming approach [that] is two orders of magnitude more efficient than standard Oct4/Sox2/Klf4/Myc-mediated methods."
Over in Molecular Cell, an international team led by investigators at Cold Spring Harbor Laboratory shows that a widely used telomeric assay to identify mutants with improper TPEV, which "employs theURA3 gene at the telomere of chromosome VII-L that can be counterselected with 5-fluoroorotic acid," is affected by 5-FOA resistance as a result of "an imbalance in ribonucleotide reductase." The team says that as a result of 5-FOA-induced metabolic changes, "certain mutants being studied are incompatible with the use of certain prototrophic markers for TPEV."
A team led by researchers at the University of California, Los Angeles, shows in Cell Metabolism this week that groucho family member TLE3 "is a dual-function transcriptional co-regulator of adipogenesis." More specifically, the UCLA-led team shows that TLE3 participates in a feed-forward loop during adipocyte differentiation in which it helps to stimulate adipogenesis, though induction of TLE3 during differentiation also "provides a mechanism for termination of Wnt signaling," such that it reverses β-catenin-dependent repression of adipocyte gene expression. In a transgenic model, the researchers found that "TLE3 in adipose tissue in vivo … ameliorates high-fat-diet-induced insulin resistance."
And in a Cell paper published online in advance, researchers at Mount Sinai School of Medicine in New York show that Trithorax complex member WD repeat domain 5 — or Wdr5, which is an effector of H3K4 methylation — "positively correlates with the undifferentiated state and is a regulator of ES [embryonic stem] cell self-renewal." Wdr5 expression, the team found, "is required for the efficient formation of induced pluripotent stem cells." As such, the authors "propose an integrated model of transcriptional and epigenetic control, mediated by select trxG members, for the maintenance of ES cell self-renewal and somatic cell reprogramming."