MOLECULAR REGULATION OF IMMUNOGLOBULIN GENE EXPRESSION

这里提出的实验涉及基因之间的关系， 组织和基因表达，因为它影响免疫球蛋白重链， 链（Igh）基因家族及其邻近基因和基因家族 12号染色体。 建立详细的联系和物理地图， 染色体，染色体特异性DNA片段分离自一个种间 体细胞杂种将用于确定限制性片段长度 多态性和分析携带亚染色体片段的杂交体。 染色体“跳跃”程序将被用来表征该区域 原癌基因c-Fos和Igh之间的关系。 从转录水平上鉴定 活性位点的染色体，差异杂交技术将是 用于分离染色体特异性、组织特异性cDNA。 的 在免疫系统发育过程中，这些蛋白的表达将是 通过原位杂交分析。 确定的结构基础 在以前的实验中发现的广泛的DNA水平多态性，等位基因 将克隆这些基因座的形式并通过限制性作图进行研究， 异源双链体分析，以及必要时的序列分析，以便 确定特定类别的事件（换位， 非同源重组）是观察到的多样性的原因。 除了这些实验应该提供的对遗传学的洞察之外， 小鼠12号染色体的组织及其功能后果 本组织的工作应有助于更普遍地确定战略， 哺乳动物基因组织的“中级”分析。

The experiments proposed here concern the relationship between gene organization and gene expression as it affects the immunoglobulin heavy chain (Igh) gene family, and neighboring genes and gene families on mouse chromosome 12. To construct detailed linkage and physical maps of the chromosome, chromosome-specific DNA fragments isolated from an interspecies somatic cell hybrid will be used to define restriction fragment length polymorphisms and to analyze hybrids carrying subchromosomal fragments. Chromosome "hopping" procedures will be used to characterize the region between the proto-oncogene c-Fos and Igh. To identify transcriptionally active loci in the chromosome, difference hybridization techniques will be used to isolate chromosome-specific, tisssue-specific cDNAs. The expression of these during the development of the immune system will be analyzed by in situ hybridization. To determine the structural basis of the extensive DNA-level polymorphism found in previous experiments, allelic forms of these loci will be cloned and studied by restriction mapping, heteroduplex analysis, and, where necessary, sequence analysis, in order to determine whether particular classes of events (transpositions, non-homologous recombinations) are responsible for the observed diversity. Beyond the insight that these experiments should provide into the genetic organization of mouse chromosome 12 and functional consequences of that organization, the work should help to define strategies more generally for the "mid-level" analysis of mammalian gene organization.