MAINTENANCE OF GENE EXPRESSION IN THE RED CELL LINEAGE

描述(改编自应用)：在红细胞分化过程中 基因组逐渐包装成异染色质和基因表达 沉默了。定义LCR和增强剂阻止的机制 沉默，LCR5‘HS2抑制转基因沉默的能力是 在K562细胞中进行了异位基因组位点的检测。含有An的活性转基因 完整的增强子在沉默时远离着丝粒异染色质 转基因更接近着丝粒异染色质。突变 这会削弱增强器抑制沉默的能力，从而导致 转基因，即使处于活跃状态，也要保持在着丝粒附近。 基因表达激活和维持的分子基础 红系细胞的定义是：1)转基因整合的分离 检测转基因和侧翼区域之间相互作用的位置。2) 确定与激活和转录因子相关的顺式序列和反式因子 沉默已定义的基因组基因座，关注与以下相关的核因子 活跃和不活跃的核舱室。3)衍生新的K562整合 无需选择要处理的表达式即可作为目标的站点 关于LCR和染色质绝缘体性质的基本问题， 4)建立小鼠模型，研究红细胞增强子功能 在体内成熟。这将使我们能够调查 红系增强剂抑制小鼠红系成熟过程中的沉默 确定体内沉默的抑制是否涉及重新定位 在细胞核内进行转基因。

DESCRIPTION (adapted from the application): During red cell differentiation the genome is progressively packaged into heterochromatin and gene expression silenced. To define the mechanisms by which LCRs and enhancers prevent silencing, the ability of LCR 5'HS2 to suppress silencing of transgenes was tested at ectopic genomic sites in K562 cells. Active transgenes containing an intact enhancer localize away from centromeric heterochromatin while silenced transgenes are in closer proximity to centromeric heterochromatin. Mutations that impair the ability of the enhancer to suppress silencing cause the transgene, even when in an active state, to remain in proximity to centromeres. The molecular basis for activation and maintenance of gene expression in erythroid cells will be defined by: 1) isolation of the transgene integration sites to examine interactions between the transgene and flanking region. 2) determining the cis sequences and trans factors associated with activation and silencing of defined genomic loci, focusing on nuclear factors associated with active and inactive nuclear compartments. 3) deriving new K562 integration sites that can be targeted without selection for expression to address fundamental questions regarding the nature of LCRs and chromatin insulators, and 4) developing a mouse model to study enhancer function during red cell maturation in vivo. This will allow investigation of the mechanism by which erythroid enhancers suppress silencing during erythroid maturation in mice and determine if suppression of silencing in vivo involves relocalization of the transgene within the nucleus.