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Recent landmark experiments have shown that transient overexpression of a small number of transcription factors can reprogram differentiated cells into induced pluripotent stem (iPS) cells that resemble embryonic stem (ES) [...]

Since the initial description of induced pluripotent stem (iPS) cells created by forced expression of four transcription factors in mouse fibroblasts, the technique has been used to generate embryonic stem [...]

Tissue macrophages comprise a heterogeneous group of cell types differing in location, surface markers and function (1). Red pulp macrophages are a distinct splenic subset involved in removing senescent red blood cells (2). Transcription factors such as PU.1 (also known as Sfpil) and C/EBPa (Cebpa) have general roles in myelomonocytic development (3,4), but the transcriptional basis for producing tissue macrophage subsets remains unknown. Here we show that Spi-C (encoded by Spic), a PU.1-related transcription factor, selectively controls the development of red pulp macrophages. Spi-C is highly expressed in red pulp macrophages, but not monocytes, dendritic cells or other tissue macrophages. [Spic.sup.-/-] mice have a cell-autonomous defect in the development of red pulp macrophages that is corrected by retroviral Spi-C expression in bone marrow cells, but have normal monocyte and other macrophage subsets. Red pulp macrophages highly express genes involved in capturing circulating haemoglobin and in iron regulation. [Spic.sup.-/-] mice show normal trapping of red blood cells in the spleen, but fail to phagocytose these red blood cells efficiently, and develop an iron overload localized selectively to splenic red pulp. Thus, Spi-C controls development of red pulp macrophages required for red blood cell recycling and iron homeostasis., Spi-C belongs to the Spi subfamily of Ets transcription factors, which includes PU.1 and Spi-B (5,6), and was initially reported to be expressed in B cells (5,7). We compared expression [...]

The lymphatic system plays a key role in tissue fluid regulation and tumour metastasis, and lymphatic defects underlie many pathological states including lymphoedema, lymphangiectasia, lymphangioma and lymphatic dysplasia (1-3). However, [...]

In yeast, the transcription factor Crz1 is dephosphorylated and translocates into the nucleus in response to extracellular calcium. Here we show, using time-lapse microscopy, that Crz1 exhibits short bursts of [...]

Abstract: Hyperhomocysteinemia is regarded as an independent risk factor for cardiovascular disorders. Although renal dysfunction or failure is one of the important factors causing hyperhomocysteinemia, the role of homocysteine (Hcy) [...]

PLoS Biol. 6, e38 (2008) Evolution has massively rewired molecular circuits controlling gene expression in yeast, Hao Li and Alexander Johnson of the University of California, San Francisco, and their [...]

Author(s): Gerald Crabtree [1] A developmental biologist muses on the magic of the egg. Many biologists, myself included, grew up watching frogs' eggs hatch into tadpoles at the warm surfaces [...]