Endocrine system

  • Article |

    In the Drosophila testis, IGF-II messenger RNA binding protein (Imp) is shown to promote stem-cell niche maintenance by stabilizing unpaired (upd) RNA; Imp levels decrease in the hub cells of older males, owing to regulation by the microRNA let-7.

    • Hila Toledano
    • , Cecilia D’Alterio
    •  & D. Leanne Jones
  • Letter |

    Circadian rhythms control many physiological functions. During periods of feeding, pancreatic islets secrete insulin to maintain glucose homeostasis — a rhythmic process that is disturbed in people with diabetes. These authors show that pancreatic islets contain their own clock: they have self-sustained circadian oscillations of CLOCK and BMAL1 genes and proteins, which are vital for the regulation of circadian rhythms. Without this clock, a cascade of cellular failure and pathology initiates the onset of diabetes mellitus.

    • Biliana Marcheva
    • , Kathryn Moynihan Ramsey
    •  & Joseph Bass
  • Article |

    In the pancreas, insulin-producing β-cells are long-lived and generally replicate seldom. They can do so, however, after increased metabolic demand or after injury. Here, a new transgenic model is developed in which β-cells are nearly completely ablated in mice. If given insulin, these mice survive, and grow new β-cells. Lineage-tracing shows that these new β-cells come from α-cells, revealing a previously disregarded degree of pancreatic cell plasticity.

    • Fabrizio Thorel
    • , Virginie Népote
    •  & Pedro L. Herrera
  • Article |

    In mammals, embryos are considered to be sexually indifferent until the action of a sex-determining gene initiates gonadal differentiation. Here it is demonstrated that this situation is different for birds. Using rare, naturally occurring chimaeric chickens where one side of the animal appears male and the other female, it is shown that avian somatic cells possess an inherent sex identity and that, in birds, sexual differentiation is cell autonomous.

    • D. Zhao
    • , D. McBride
    •  & M. Clinton
  • Article |

    Pancreatic β-cells release insulin, which controls energy homeostasis in vertebrates, and its lack causes diabetes mellitus. The transcription factor neurogenin 3 (Neurog3) initiates differentiation of β-cells and other islet cell types from pancreatic endoderm; here, the transcription factor Rfx6 is shown to direct islet cell differentiation downstream of Neurog3 in mice and humans. This may be useful in efforts to generate β-cells for patients with diabetes.

    • Stuart B. Smith
    • , Hui-Qi Qu
    •  & Michael S. German