DEVELOPMENTAL CONTROL OF INTRODUCED GENES IN RODENTS

我们建议研究特定DNA序列的作用，以及 这些序列在发育过程中基因组中的位置 基因表达的调控。 小鼠乳腺肿瘤克隆片段 病毒（MTV），其转录是由糖皮质激素诱导，将是 通过显微注射引入小鼠受精卵。 注射的胚胎将 被植入到寄养母亲，和成年小鼠从这些衍生 受精卵 这些小鼠将被培育， 在不同的染色体位点引入MTV的拷贝。 Southern印迹 分析将用于鉴定含有新获得的 序列，而从组织中分离的RNA的北方印迹分析 这些小鼠将用于确定病毒序列在哪些组织中 表达了。 这些外源引入的DNA将包含： 从整个前病毒;含有基因缺失的前病毒 体外工程化;连接HSV-1胸苷的前病毒元件 激酶基因;或与鼠和人c-myc基因连接的前病毒元件。 我们的目标是确定病毒序列和/或染色体 MTV的位置决定其在乳腺中的类固醇调节表达 以及外源引入的序列是否将在组织中表达。 非乳腺组织 我们还将确定MTV序列是否可以 在激素和发育调节中对非病毒DNA产生影响 时尚. 因为MTV基因的表达是由神经系统控制的， 仅限于哺乳期乳腺和小鼠肿瘤， 所描述的将导致对涉及的机制的理解， 类固醇诱导基因调控的发展。

We propose to examine the role of specific DNA sequences, and the effect of the position of these sequences within the genome on the developmental regulation of gene expression. Cloned fragments of mouse mammary tumor virus (MTV), whose transcription is induced by glucocorticoids, will be introduced into mouse zygotes by microinjection. The injected embryos will be implanted into foster mothers, and adult mice derived from these zygotes. These mice will then be bred to give offspring with exogenously introduced copies of MTV at different chromosomal loci. Southern blot analysis will be used to identify mice that contain newly acquired sequences, while Northern blot analysis of RNA isolated from tissues of these mice will be used to determine in which tissues the viral sequences are expressed. These exogenously introduced DNAs will contain: sequences from the whole provirus; proviruses containing deletions genetically engineered in vitro; proviral elements to ligated the HSV-1 thymidine kinase gene; or proviral elements ligated to murine and human c-myc genes. Our goal is to determine whether the viral sequences and/or the chromosomal position of MTV determines its steroid-regulated expression in mammary tissue and whether an exogenously introduced sequence will be expressed in non-mammary tissue. We will also determine whether the MTV sequences can exert an effect on nonviral DNA in a hormonal and developmentally regulated fashion. Because MTV gene expression is hormonally controlled and is restricted to lactating mammary glands and tumors in mice, the approach described will lead to an understanding of the mechanisms involved in the development of regulation of a steroid inducible gene.