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Transgenic System (transgenic + system)
Selected AbstractsDevelopmental elimination of ectopic projection sites for the transgenic OR gene that has lost zone specificity in the olfactory epitheliumEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2003Hiroko Nakatani Abstract In rodents, olfactory receptor (OR) genes are expressed in one of four zones in the olfactory epithelium (OE), and olfactory sensory neurons (OSNs) expressing the same OR project their axons to a specific set of glomeruli on the olfactory bulb (OB). Using the yeast artificial chromosome (YAC) transgenic system, we have analysed the expression of the murine OR gene MOR29A of the MOR28 cluster located on chromosome 14. Although expression of the endogenous MOR29A was restricted to the most dorsomedial zone, the transgenic MOR29A (Tg MOR29A) was expressed in all four zones of the OE. When the OB of the transgenic mouse was analysed, the axons of the OSNs expressing Tg MOR29A were found to project not only to the dorsal side but also to the ventral side of the OB as well. The ectopic projection sites on the ventral side gradually disappear during postnatal development. Naris occlusion prevents this elimination, suggesting that odorant stimulation is involved in eliminating the ectopic projection sites. [source] Construction and characterization of a doxycycline-inducible transgenic system in Msx2 expressing cellsGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 5 2009Congxing Lin Abstract Homeobox gene Msx2 is widely expressed during both embryogenesis and postnatal development and plays important roles during organogenesis. We developed an Msx2 -rtTA BAC transgenic line which can activate TetO-Cre expression in Msx2 -expressing cells upon doxycycline (Dox) treatment. Using the Rosa26-LacZ (R26R) reporter line, we show that rtTA is activated in Msx2 -expressing organs including the limb, heart, external genitalia, urogenital system, hair follicles and craniofacial regions. Moreover, we show that in body appendages, the transgene can be activated in different domains depending on the timing of Dox treatment. In addition, the transgene can also be effectively activated in adult tissues such as the hair follicle and the urogenital system. Taken together, this Msx2 -rtTA;TetO-Cre system is a valuable tool for studying gene function in the development of the aforementioned organs in a temporal and spatially-restricted manner, as well as for tissue lineage tracing of Msx2 -expressing cells. When induced postnatally, this system can also be used to study gene function in adult tissues without compromising normal development and patterning. genesis 47:352,359, 2009. © 2009 Wiley-Liss, Inc. [source] Preferential Priming of Alloreactive T Cells with Indirect ReactivityAMERICAN JOURNAL OF TRANSPLANTATION, Issue 4 2009T. V. Brennan The relative contributions of the direct and indirect pathways in alloimmune responses have not been fully elucidated. We report a novel murine TCR transgenic system that can simultaneously track the CD4-direct (CD4-d), CD4-indirect (CD4-i) and CD8-direct (CD8-d) pathways after transplantation. Using this system, we have observed a profoundly greater proliferation of CD4-i T cells relative to CD4-d and CD8-d T cells after transplantation. Furthermore, a much larger proportion of CD4-i T cells attain an effector phenotype. We also analyzed endogenous, wild-type T cells using enzyme-linked immunospot analysis. In naïve mice, T cells with indirect reactivity were undetectable, but T cells with direct reactivity were abundant. However, 10 days after skin or heterotopic heart transplantation, CD4-i T cells comprised approximately 10% of the CD4+ response. Consistent with increased priming of the CD4-i pathway, we observed that the CD4-i T cells were further enriched in the effector cells migrating to the allograft and in memory-like T cells persisting after rejection. Thus, priming of the CD4-i pathway is favored after transplantation, allowing a rare population to rapidly become a major component of the CD4+ T-cell response in acute allograft rejection. The generalizability of this observation to other models remains to be determined. [source] Manipulating gene activity in Wnt1-expressing precursors of neural epithelial and neural crest cellsDEVELOPMENTAL DYNAMICS, Issue 1 2010Wei Hsu Abstract Targeted gene disruption or expression often encounters lethality. Conditional approaches, permitting manipulation at desired stages, are required to overcome this problem in order to analyze gene function in later developmental processes. Wnt1 has been shown to be expressed in neural crest precursors at the dorsal midline region. However, its expression was not detected in emigrated neural crest cells, the descendants of Wnt1-expressing precursors. We have developed mouse transgenic systems to manipulate gene activity in the Wnt1-expressing precursors and their derivatives by integrating the tetracycline-dependent activation and Cre-mediated recombination methods. A new Wnt1-rtTA strain, carrying rtTA under control of Wnt1 regulatory elements, has been created for gene manipulation in a spatiotemporal-specific fashion. Together with our previously developed Wnt1-Cre;R26STOPrtTA model, these systems permit conditional gene expression and ablation in pre-migratory and/or post-migratory neural crest cells. This study demonstrated the versatility of our mouse models to achieve gene manipulation in early neural development. Developmental Dynamics 239:338,345, 2010. © 2009 Wiley-Liss, Inc. [source] | ||||||||||