Regulatory mechanisms for the MHC class III genes

小鼠C4和性限制蛋白（Slp）是由小鼠主要组织相容性复合体III的两个最近重复的基因编码的。小鼠品系中这些基因的许多表达变体的可用性使它们成为有吸引力的系统，其中可以研究发育，激素和组织特异性控制下的真核基因的调节。我们分离和表征的cDNA和基因组DNA克隆，这些基因从几个小鼠品系表现出有趣的变化C4和slp的表达。我们通过各种分子遗传学技术获得的实验结果可以总结如下.携带H-2^k单倍型的小鼠品系被表征为低C4生产者。我们用北方印迹法测定了C4 mRNA，用核运行法测定了来自高C4产生小鼠（B10）和低C4产生小鼠（B10.BR）的肝细胞的核C4 RNA。此外，我们测试了来自这些菌株的C4基因的5 '侧翼区，以确定它们的反式表达。 关于我们 转染细胞的功能性调节活性。结果表明，C4双合成的低水平主要受转录后和翻译前水平的调控.为了阐明C4基因（组成型）和Slp基因（睾酮诱导型）表达模式差异的分子基础，我们比较了从FM株分离的这两个基因的核苷酸序列。此外，我们在转染的细胞中使用CAT分析测试了5 '侧翼区片段的转录调控活性。我们确定了这些基因区域中的功能结构域，这些功能结构域似乎可以解释C4和Slp基因表达的差异。我们从C3H.W7菌株的粘粒文库中分离并鉴定了所有C4相关基因，该菌株显示了Slp的异常表达模式（组成表达）。我们发现这三个明显的Slp基因确实由C4衍生的5'半和Slp衍生的3'半组成。通过与C4和Slp基因的核苷酸序列比较，我们得出结论，这些重组基因是由基因中部的多个交叉衍生的。少

Mouse C4 and Sex-limited protein(Slp) are encoded by two recently duplicated genes of the major histocompatibility complex III of the mouse. The availability of many expression variants for these genes among mouse strains makes them the attractive system in which the regulation of eukaryotic genes under developmental, hormonal and tissue specific control can be studied. We isolated and characterized cDNA and genomic DNA clones for these genes from several mouse strains which show interesting variation for the expression of C4 and slp. Our experimental results obtained by various molecular genetic techniques can be summarized as follows.1. The mouse strains carrying H-2^k haplotype are characterized as low C4 producers. We measured C4 mRNA by Northern blotting and nuclear C4 RNA by nuclear run on assay using the hepatocytes from high C4 producing mouse(B10) and low C4 producing mouse(B10.BR). Furthermore we tested the 5'flanking regions of the C4 genes from these strains for their trans … More criptional regulatory activity with transfected cells. The results clearly showed that the low C4 bisynthesis is mainly controlled at the posttranscriptional and pretranslational level.2. To elucidate the molecular basis underlying the difference in the mode of expression of C4 gene(constitutional) and Slp gene(testosterone induced), we compared the nucleotide sequences of these two genes isolated from FM strain. Furthermore we tested the 5'flanking region fragments for transcriptional regulatory cativity using CAT assay in transfected cells. We identified the functional domains in the regions of these genes that appear to explain the difference in the gene expression of the C4 and Slp genes.3. We isolated and characterized all of C4-related genes from the cosmid library of C3H.W7 strain that shows an extraordinary mode of expression of Slp(constitutional expression). We found the three of apparent Slp genes indeed consisting of the C4-derived 5' half and Slp-derived 3' half. By comparing their nucleotide seguences with those of C4 and Slp genes, we concluded that these recombinant genes are derived by multiple cross over in the central portions of the gene. Less