STRUCTURE AND EXPRESSION OF COMPLEMENT GENES

小鼠组织相容性复合体(H-2)的S区域是 几乎在25年前被定义为控制着 小鼠血清中SS(血清物质)的含量。后续 来自多个实验室的研究表明，SS是 由两种不同的蛋白质组成：C4，小鼠的第四种 补体的组成部分，以及性限制蛋白(SLP)，一种蛋白质 与C4有着广泛的结构和生化相同之处 但缺乏C4活性。SLP值得注意的是它的表达方式 是睾丸素依赖的，因此仅限于某些男性 菌株而在其他菌株中的表达是独立于 睾丸素或相反，完全检测不到。近期 我们实验室的核酸克隆和测序研究以及 其他人已经证明了C4和SLP是由DISTINCT编码的 位于S地区的构造基因，无疑是 基因复制的产物。 拟议方案的目标是(A)确定和 比较C4和SLP基因的结构组织；(B) 了解结构和进化关系 在这些基因和其他基因之间，特别是I类和 H-2复合体的II类基因及其相关基因 补体蛋白C3和C5；以及(C)鉴定 控制性别、组织和紧张的分子机制- C4和SLP基因的特异性表达。 我们建议使用重组DNA克隆和测序 方法(A)对C4的整个转录区域进行测序 和SLP基因；。(B)扩大我们对上游区域的研究。 利用限制性内切酶定位C4和SLP基因 和DNA测序；(C)对基因上游区域进行测序 小鼠C4和SLP基因的转录起始点 表现出不同C4和SLP表达表型的菌株；以及 (D)使用定点突变和DNA重建方法， 以及在细胞培养中表达的方法来鉴定 调控C4和SLP的基因片段 表情。

The S region of the murine histocompatibility complex (H-2) was defined almost 25 years ago as a genetic locus controlling the quantity of Ss (serum substance) in mouse serum. Subsequent work from a number of laboratories established that Ss is composed of two distinct proteins: C4, the murine fourth component of complement, and sex-limited protein (Slp), a protein that shares extensive structural and biochemical identity with C4 but which lacks C4 activity. Slp is notable in that its expression is testosterone-dependent and hence limited to males in some strains while in other strains expression is either independent of testosterone or conversely completely undetectable. Recent nucleic acid cloning and sequencing studies in our laboratory and others have demonstrated that C4 and Slp are encoded by distinct structural genes that lie in the S region and are doubtless the products of gene duplication. The goals of the proposed program are (a) to determine and compare the structural organization of the C4 and Slp genes; (b) to understand the structural and evolutionary relationships between these genes and other genes, in particular the class I and class II genes of the H-2 complex and the genes for the related complement proteins C3 and C5; and (c) to characterize the molecular mechanisms controlling sex-, tissue-, and strain- specific expression of the C4 and Slp genes. We propose to use recombinant DNA cloning and sequencing methods (a) to sequence the entire transcribed regions of the C4 and Slp genes; (b) to extend our study of upstream regions of the C4 and Slp genes by mapping restriction enzyme cleavage sites and by DNA sequencing; (c) to sequence regions upstream of the transcription initiation sites of C4 and Slp genes from mouse strains that exhibit varied C4 and Slp expression phenotypes; and (d) to use site-specific mutation and DNA reconstruction methods, together with methods for expression in cell culture to identify the gene segments responsible for regulating C4 and Slp expression.