Featured
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The let-7–Imp axis regulates ageing of the Drosophila testis stem-cell niche
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
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News |
Egg-making stem cells found in adult ovaries
Discovery could pave the way for new fertility treatments and a longer reproductive life.
- Kendall Powell
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News & Views |
Organ recital in a dish
It is difficult to recapitulate organ development in vitro, especially when interactions between tissues are essential. Nonetheless, researchers have now achieved this for the pituitary gland. See Article p.57
- Karine Rizzoti
- & Robin Lovell-Badge
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Article |
PDGF signalling controls age-dependent proliferation in pancreatic β-cells
- Hainan Chen
- , Xueying Gu
- & Seung K. Kim
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Letter |
DMRT1 prevents female reprogramming in the postnatal mammalian testis
- Clinton K. Matson
- , Mark W. Murphy
- & David Zarkower
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News |
Sperm grown in a test tube
Immature mouse testicles yield fully developed sperm in culture.
- Janelle Weaver
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Letter |
Disruption of the clock components CLOCK and BMAL1 leads to hypoinsulinaemia and diabetes
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
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News & Views |
Extreme makeover of pancreatic α-cells
Most insulin-secreting pancreatic β-cells are irreplaceably lost in type 1 diabetes. In a mouse model, pancreatic α-cells seem to sacrifice their identity to replenish the low stock of β-cells
1 . Two experts discuss what this means for understanding the basic cell biology involved and its relevance to treating diabetes.boxed-text - Kenneth S. Zaret
- & Morris F. White
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Article |
Conversion of adult pancreatic α-cells to β-cells after extreme β-cell loss
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
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Article |
Somatic sex identity is cell autonomous in the chicken
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
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Article |
Rfx6 directs islet formation and insulin production in mice and humans
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