DIFFERENTIATION OF TERATOCARCINOMA CELLS: REGULATION

这个项目的目标是(1)了解两个基因的结构 其表达受维甲酸控制，以及(2)鉴定 参与IV型胶原等顺式作用的DNA元件 F9干细胞分化过程中的分化基因。我计划这样做 检查这两个特定于F9的差异的限制图 基因，识别结构区域，更具体地说是‘5末端 转录顶端的位置。两个不同大小的‘5侧翼区域 基因将与β-珠蛋白结构基因连锁，其启动子和‘3 基因末端已被删除。用杂交法进行基因转染法 基因-SV40载体作为供体将在F9干细胞中进行。维甲酸 将在转基因细胞中检测到对酸敏感的DNA元件 当检测到贝塔-珠蛋白基因在 F9细胞的分化阶段。这一系列的实验将使 我直接鉴定维甲酸调控的序列或 间接的。维甲酸被认为与控制 在上皮组织和其他一些细胞类型中的分化。这个 维甲酸诱导畸胎癌分化的机制 对细胞的了解还不是很清楚。这一领域的调查推测 维甲酸的作用方式类似于类固醇激素。然而， 实验数据还太初步，不能得出任何确定的结论。这个 以分子c DNA为探针研究分化基因 维甲酸调节元件的进一步鉴定将告诉我们 维甲酸作用的潜在机制。此外, 对早期胚胎分化的理解也可能有助于 人卵巢癌去分化致癌机制的认识 有些案子。

The goals of this project are (1) to understand the structure of two genes of which expression is controlled by retinoic acid and (2) to identify cis-acting DNA elements involved in the collagen IV and another differentiation gene during F9 stem cell differentiation. I plan to examine the restriction maps of these two F9 differentiation specific genes, identify the structural regions and more specifically the '5 end transcription cap sites. Different sizes of '5 flanking regions of two genes will be linked to Beta-globin structure gene of which promotor and '3 end of gene has been deleted. Transfection assays by using hybrid gene-SV40 vector as donor will be performed in F9 stem cells. The retinoic acid sensitive DNA elements will be determined in the transfected cells when higher degree of expression of Beta-globin gene is detected at the differentiated stage of F9 cells. These series of experiments will allow me to identify the retinoic acid regulated sequences directly or indirectly. Retinoic acid has been implicated in the control of differentiation in epithelial tissues and in some other cell types. The mechanism by which retinoic acid induce differentiation of teratocarcinoma cells is not well understood. Investigation in this field speculate that retinoic acid may act in a manner analogous to steroid hormones. However, the experimental data is too preliminary to make any firm conclusions. The studies of differentiation genes by using molecular cDNA as probe and further identifications of retinoic acid regulatory elements will inform us of the underlying mechanism of the action of retinoic acid. In addition, the understanding of early embryonic differentiation may also facilitate the understanding of oncogenesis which results from dedifferentiation in some cases.