ALPHA-FETOPROTEIN GENE REGULATION IN LIVER PATHOLOGY

损伤后，肝脏将经历受控的代偿性生长 使器官恢复到原来的质量。非常精确的机械装置 必须控制这一过程，感知增长和停止的要求 当达到正确的大小时，它就会被激活。然而，慢性再生或 使用各种药物的长期治疗将克服这种控制， 导致肿瘤的发生。肝脏再生伴随着 基因表达，包括甲胎蛋白(AFP)表达 吉恩。甲胎蛋白是一种所谓的胎儿抗原--在胎儿时期表达，但 不是在出生后，然后在肝脏再生和 肿瘤发生学。AFP在肝再生中的表达水平为 受遗传基因Rif控制，指定较低的AFP mRNA水平 C57BL/6小鼠在再生过程中。这一现象的生物学意义 观察是未知的，但它确实与i中的差异相关 对肿瘤的易感性。我们的长期目标是理解 受控再生生长过程中基因调控的差异 不受控制的致瘤生长。甲胎蛋白基因将被用作 在肝脏再生和肿瘤发生过程中表达的基因。 首先将确定肝脏中AFP mRNA水平的升高是否 再生是转录或转录后的结果 活动，通过直接测量制作的成绩单的数量 随着时间的推移。基因座的哪些区域是导致这种增加的原因 肝再生过程中甲胎蛋白水平？携带转基因的小鼠 由驱动标记基因表达的AFP基因座的区域组成 将在肝脏再生过程中进行表达测试。这一战略 将定位所需的区域，允许在体外使用 基因调控因子(S)的鉴定与克隆技术 表情。活性基因周围的染色质通常与 转录导致其核酸酶敏感性的非活性基因 因子结合。将绘制并比较核酸酶敏感部位 那些已经在正常成人和胎儿肝脏中发现的基因。压力是不是 MRNA水平的依赖差异是诱导机制的一部分， 或者它是独立的，反映了基因表达的其他差异。这 将通过实验比较两个小鼠品系的结果来解决 C57BL/6和C3H/He。

After injury the liver will undergo controlled compensatory growth restoring the organ to its original mass. Remarkably precise mechanisms must control this process, sensing the requirement for growth and stopping it when the correct size is reached. However, chronic regeneration or prolonged treatment with a variety of agents will overcome this control, leading to tumorigenesis. Liver regeneration is accompanied by changes in gene expression, including the expression of the alpha-Fetoprotein (AFP) gene. AFP is a so called fetal antigen--expressed during fetal life, but not after birth, then expressed again during liver regeneration and tumorigenesis. The level of AFP expression in liver regeneration is controlled by the genetic locus, Rif, specifying lower AFP mRNA levels in C57BL/6 mice during regeneration. The biological significance of this observation is unknown, but it does correlate with differences in I susceptibility to tumorigenesis. The long term goal is to understand differences in gene regulation during controlled regenerative growth versus uncontrolled tumorigenic growth. The AFP gene will be used as a model for genes expressed during liver regeneration and tumorigenesis. It will first be determined if the increase in AFP mRNA levels during liver regeneration is the result of transcriptional or post-transcriptional activities, by direct measurement of the number of transcripts produced over time. Which regions of the locus are responsible for the increase levels of AFP during liver regeneration? Mice carrying transgenes consisting of regions of the AFP locus driving expression of a marker gene will be tested for expression during liver regeneration. This strategy will localize the region required, permitting the use of in vitro techniques to identify and clone the factor(s) responsible for gene expression. The chromatin surrounding active genes usually differs from inactive genes in its nuclease sensitivity, as a result of transcription factor binding. Nuclease hypersensitive sites will be mapped and compared to those already found in the normal adult and fetal liver. Are the strain dependent differences in mRNA levels a part of the mechanism of induction, or is it separate, reflecting other differences in gene expression. This will be addressed by experiments comparing results for 2 mouse strains C57BL/6 and C3H/He.