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M. Foster E. Montecino-Rodriguez R. Clark K. Dorshkind 《Cellular and molecular life sciences : CMLS》1998,54(10):1076-1082
Hormones produced by the anterior pituitary gland have been implicated in the regulation of primary lymphocyte development.
In order to identify endocrine factors involved in that process, several strains of mice with genetic defects resulting in
a selective impairment in the production of one or more anterior pituitary-derived hormones have been analysed. This study
has resulted in the classification of endocrine hormones into the following four categories (i) hormones such as prolactin
with no apparent effects on primary lymphopoiesis; (ii) anabolic hormones such as growth hormone and insulin-like growth factor-I
whose stimulatory effects on primary lymphopoiesis are non-lineage-specific and related to their actions as systemic mediators
of growth and/or differentiation; (iii) hormones such as thyroid hormones that have an obligate role in primary B lymphopoiesis;
and (iv) hormones such as oestrogens that act as negative regulators of lymphopoiesis. 相似文献
116.
Squyres SW Aharonson O Arvidson RE Bell JF Christensen PR Clark BC Crisp JA Farrand W Glotch T Golombek MP Grant J Grotzinger J Herkenhoff KE Johnson JR Jolliff BL Knoll AH McLennan SM McSween HY Moore JM Rice JW Tosca N 《Nature》2006,443(7107):E1-2; discussion E2
The Mars Exploration Rover Opportunity discovered sulphate-rich sedimentary rocks at Meridiani Planum on Mars, which are interpreted by McCollom and Hynek as altered volcanic rocks. However, their conclusions are derived from an incorrect representation of our depositional model, which is upheld by more recent Rover data. We contend that all the available data still support an aeolian and aqueous sedimentary origin for Meridiani bedrock. 相似文献
117.
Interactive memory systems in the human brain. 总被引:24,自引:0,他引:24
R A Poldrack J Clark E J Paré-Blagoev D Shohamy J Creso Moyano C Myers M A Gluck 《Nature》2001,414(6863):546-550
Learning and memory in humans rely upon several memory systems, which appear to have dissociable brain substrates. A fundamental question concerns whether, and how, these memory systems interact. Here we show using functional magnetic resonance imaging (FMRI) that these memory systems may compete with each other during classification learning in humans. The medial temporal lobe and basal ganglia were differently engaged across subjects during classification learning depending upon whether the task emphasized declarative or nondeclarative memory, even when the to-be-learned material and the level of performance did not differ. Consistent with competition between memory systems suggested by animal studies and neuroimaging, activity in these regions was negatively correlated across individuals. Further examination of classification learning using event-related FMRI showed rapid modulation of activity in these regions at the beginning of learning, suggesting that subjects relied upon the medial temporal lobe early in learning. However, this dependence rapidly declined with training, as predicted by previous computational models of associative learning. 相似文献
118.
Grbić M Van Leeuwen T Clark RM Rombauts S Rouzé P Grbić V Osborne EJ Dermauw W Ngoc PC Ortego F Hernández-Crespo P Diaz I Martinez M Navajas M Sucena É Magalhães S Nagy L Pace RM Djuranović S Smagghe G Iga M Christiaens O Veenstra JA Ewer J Villalobos RM Hutter JL Hudson SD Velez M Yi SV Zeng J Pires-daSilva A Roch F Cazaux M Navarro M Zhurov V Acevedo G Bjelica A Fawcett JA Bonnet E Martens C Baele G Wissler L Sanchez-Rodriguez A Tirry L Blais C Demeestere K Henz SR Gregory TR Mathieu J 《Nature》2011,479(7374):487-492
119.
Jirawatnotai S Hu Y Michowski W Elias JE Becks L Bienvenu F Zagozdzon A Goswami T Wang YE Clark AB Kunkel TA van Harn T Xia B Correll M Quackenbush J Livingston DM Gygi SP Sicinski P 《Nature》2011,474(7350):230-234
Cyclin D1 is a component of the core cell cycle machinery. Abnormally high levels of cyclin D1 are detected in many human cancer types. To elucidate the molecular functions of cyclin D1 in human cancers, we performed a proteomic screen for cyclin D1 protein partners in several types of human tumours. Analyses of cyclin D1 interactors revealed a network of DNA repair proteins, including RAD51, a recombinase that drives the homologous recombination process. We found that cyclin D1 directly binds RAD51, and that cyclin D1-RAD51 interaction is induced by radiation. Like RAD51, cyclin D1 is recruited to DNA damage sites in a BRCA2-dependent fashion. Reduction of cyclin D1 levels in human cancer cells impaired recruitment of RAD51 to damaged DNA, impeded the homologous recombination-mediated DNA repair, and increased sensitivity of cells to radiation in vitro and in vivo. This effect was seen in cancer cells lacking the retinoblastoma protein, which do not require D-cyclins for proliferation. These findings reveal an unexpected function of a core cell cycle protein in DNA repair and suggest that targeting cyclin D1 may be beneficial also in retinoblastoma-negative cancers which are currently thought to be unaffected by cyclin D1 inhibition. 相似文献