NON-MENDELIAN INHERITANCE OF MACRONOCLEAR TRAITS

这项提议的主要目的是阐明一种 在草履虫tetraurelia的非孟德尔遗传不寻常的类型。 我们 将联合收割机结合分子生物学和遗传学来研究突变细胞系 (d48)含有A型可变表面抗原的完整拷贝 基因在微核中，但不在大核中。 野生型细胞质 允许将这些序列掺入大核中，但在 d48细胞质染色体错误断裂，A基因 的页面不存在或 最近的实验表明， d48与含有A抗原基因的重组克隆（pSA14SB）的融合， 正确处理的微核A基因序列， 下一个大核的形成（K. Aufderheide，个人 通信）。 通过显微注射pSA 14SB的特异性片段， d48大核，我们将定义正确的DNA序列所必需的。 A基因的加工。 将进行进一步的实验， 确定来自这些序列的RNA产物是否对它们的 功能 将来自d48和野生型细胞系的胞核DNA进行扩增。 分离并用于比较微核序列的组织 围绕着染色体断裂点。 最近分离出了其他非孟德尔突变体， B表面抗原基因的表达（J.Preer，个人 通信）。 我们将克隆B基因，并确定是否类似 这些突变涉及分子机制。 我们相信这项研究将促进对发育的理解 控制真核生物中的DNA重排，也许揭示了新的 核酸加工的各个方面。

The broad aim of this proposal is to elucidate the molecular details of an unusual type of non-Mendelian inheritance in Paramecium tetraurelia. We will combine molecular biology and genetics to study a mutant cell line (d48) that contains a complete copy of the A type variable surface antigen gene in the micronucleus but not in the macronucleus. Wild type cytoplasm allows the incorporation of these sequences into the macronucleus, but in d48 cytoplasm the chromosome is broken incorrectly and the A gene is deleted. Recent experiments have shown that macronuclear transformation of d48 with a recombinant clone containing the A antigen gene (pSA14SB) leads to the correct processing of the micronuclear A gene sequences during the formation of the next macronucleus (K. Aufderheide, personal communication). By microinjecting specific fragments of pSA14SB into the d48 macronucleus we will define the DNA sequences necessary for the correct processing of the A gene. Further experiments will be performed to determine if RNA products from these sequences are important for their function. Micronuclear DNA from the d48 and wild type cell lines will be isolated and used to compare the organization of the micronuclear sequences surrounding the chromosome breakage sites. Additional non-Mendelian mutants have recently been isolated that affect expression of the B surface antigen gene (J. Preer, personal communication). We will clone the B gene and determine if similar molecular mechanisms are involved in these mutations. We believe this research will advance the understanding of developmentally controlled DNA rearrangements in eukaryotes, and perhaps reveal novel aspects of nucleic acid processing.