899 research outputs found

    The role of Sox9 in mouse mammary gland development and maintenance of mammary stem and luminal progenitor cells.

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    BackgroundIdentification and characterization of molecular controls that regulate mammary stem and progenitor cell homeostasis are critical to our understanding of normal mammary gland development and its pathology.ResultsWe demonstrate that conditional knockout of Sox9 in the mouse mammary gland results in impaired postnatal development. In short-term lineage tracing in the postnatal mouse mammary gland using Sox9-CreER driven reporters, Sox9 marked primarily the luminal progenitors and bipotent stem/progenitor cells within the basal mammary epithelial compartment. In contrast, long-term lineage tracing studies demonstrate that Sox9+ precursors gave rise to both luminal and myoepithelial cell lineages. Finally, fate mapping of Sox9 deleted cells demonstrates that Sox9 is essential for luminal, but not myoepithelial, lineage commitment and proliferation.ConclusionsThese studies identify Sox9 as a key regulator of mammary gland development and stem/progenitor maintenance

    Shuttling components of nuclear import machinery involved in nuclear translocation of steroid receptors exit nucleus via exportin-1/CRM-1* independent pathway

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    AbstractThe nucleocytoplasmic transport processes are mediated by soluble transport factors constantly navigating between nuclear and cytoplasmic compartments. Our understanding about nuclear export of general ‘nuclear import factors’ that deliver the cargo to the nucleus is still fragmentary. Utilizing green fluorescent protein tagged glucocorticoid receptor (GR) and relA as our working model and with judicious use of LMB, we show in living cells that all the soluble components of the nuclear import machinery exit nucleus via exportin1/CRM1 independent pathway(s)

    CD8 T-Cell Responses in Incident and Prevalent Human Papillomavirus Types 16 and 18 Infections

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    CD8 T-cell responses were examined in subjects with incident (new following negative visits) or prevalent (lasting ≥ 4 months) human papillomavirus type 16 (HPV16) or human papillomavirus (HPV18) infection. The groups were chosen from a cohort of women being followed every 4 months with cervical cytology and HPV-DNA testing. Enzyme-linked immunospot (ELISPOT) assay was performed at enrollment (time zero) and one year later. At time zero, 1 (6%) of 17 subjects with incident HPV 16/18 infections had positive ELISPOT results which increased to 6 (35%) at one year. For the subjects with prevalent HPV 16/18 infections, the ELISPOT results were similar at time zero (2 (15%) of 15 subjects positive) and at one year (3 (20%)). While all of the 11 women with prevalent HPV16 infection showed clearance one year later, unexpectedly only 1 (25%) of 4 women with prevalent HPV18 infection demonstrated clearance one year later (P = .009)

    Large effects on \BsBs mixing by vector-like quarks

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    We calculate the contributions of the vector-like quark model to \BsBs mixing, taking into account the constraints from the decay BXsγB\to X_s\gamma. In this model the neutral bosons mediate flavor-changing interactions at the tree level. However, \BsBs mixing is dominated by contributions from the box diagrams with the top quark and the extra up-type quark. In sizable ranges of the model parameters, the mixing parameter xsx_s is much different from the standard model prediction.Comment: 11 pages, 4 figures, To be published in Phys. Rev.

    Cardiovascular magnetic resonance tagging imaging correlates with myocardial dysfunction and T2 mapping in idiopathic dilated cardiomyopathy

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    To evaluate the details of myocardial dysfunction in dilated cardiomyopathy (DCM) patients using tagging images and the correlation of tagging imaging with tissue characteristics. C

    A unique B2 B cell subset in the intestine

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    Over 80% of the body's activated B cells are located in mucosal sites, including the intestine. The intestine contains IgM+ B cells, but these cells have not been characterized phenotypically or in terms of their developmental origins. We describe a previously unidentified and unique subset of immunoglobulin M+ B cells that present with an AA4.1−CD21−CD23− major histocompatibility complex class IIbright surface phenotype and are characterized by a low frequency of somatic hypermutation and the potential ability to produce interleukin-12p70. This B cell subset resides within the normal mucosa of the large intestine and expands in response to inflammation. Some of these intestinal B cells originate from the AA4.1+ immature B2 cell pool in the steady state and are also recruited from the recirculating naive B cell pool in the context of intestinal inflammation. They develop in an antigen-independent and BAFF-dependent manner in the absence of T cell help. Expansion of these cells can be induced in the absence of the spleen and gut-associated lymphoid tissues. These results describe the existence of an alternative pathway of B cell maturation in the periphery that gives rise to a tissue-specific B cell subset

    An Enigmatic Stramenopile Sheds Light on Early Evolution in Ochrophyta Plastid Organellogenesis

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    Ochrophyta is an algal group belonging to the Stramenopiles and comprises diverse lineages of algae which contribute significantly to the oceanic ecosystems as primary producers. However, early evolution of the plastid organelle in Ochrophyta is not fully understood. In this study, we provide a well-supported tree of the Stramenopiles inferred by the large-scale phylogenomic analysis that unveils the eukaryvorous (nonphotosynthetic) protist Actinophrys sol (Actinophryidae) is closely related to Ochrophyta. We used genomic and transcriptomic data generated from A. sol to detect molecular traits of its plastid and we found no evidence of plastid genome and plastid-mediated biosynthesis, consistent with previous ultrastructural studies that did not identify any plastids in Actinophryidae. Moreover, our phylogenetic analyses of particular biosynthetic pathways provide no evidence of a current and past plastid in A. sol. However, we found more than a dozen organellar aminoacyl-tRNA synthases (aaRSs) that are of algal origin. Close relationships between aaRS from A. sol and their ochrophyte homologs document gene transfer of algal genes that happened before the divergence of Actinophryidae and Ochrophyta lineages. We further showed experimentally that organellar aaRSs of A. sol are targeted exclusively to mitochondria, although organellar aaRSs in Ochrophyta are dually targeted to mitochondria and plastids. Together, our findings suggested that the last common ancestor of Actinophryidae and Ochrophyta had not yet completed the establishment of host–plastid partnership as seen in the current Ochrophyta species, but acquired at least certain nuclear-encoded genes for the plastid functions
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