NUCLEAR DIFFERENTIATION IN TETRAHYMENA

单细胞真核生物，嗜热四膜虫，有两种 细胞核：二倍体微核（MIC），可以 进行减数分裂; 45 C大核（MAC），体细胞核， 从微核产物中取代了每一个有性世代。 长期 这项研究的目的是研究 在MAC的发展和分化的基础上，在此期间， 发生基因组改变。 我们将使用特定的克隆MIC序列， 用从MIC或MAC获得的DNA在不同温度下进行杂交实验， 阶段和分化的状态，以找出：（一）当改变 在MAC的生命周期内发生;（ii）它们是否随机发生; (iii)被改变的MIC序列如何分布在MIC上 （iv）被改变的序列是否被转录;（v） 哪些过程导致基因组改变;（vi）哪些序列是 与这些过程有关。 首先，我们将重点关注特殊类型的 序列的 然后，我们将尝试分离一个特定的基因， 一种蛋白质 我们的方法包括细胞克隆，基因克隆， 染色体作图，限制性酶切作图，基因组DNA印迹分析， 特异性探针、电子显微镜、DNA测序和其他生物化学方法。 程序. 这些研究应该有助于理解 DNA分子的改变发生在真核生物的正常细胞中 在发育和分化过程中。

The unicellular eukaryote, Tetrahymena thermophila, has two kinds of nuclei: the diploid micronucleus (MIC), the germline nucleus which can undergo meiosis; the 45C macronucleus (MAC), the somatic nucleus which is replaced each sexual generation from micronuclear products. The long-term goal of the proposed research is to investigate the molecular events underlying the development and differentiation of the MAC, during which, genome alterations occur. We will use specific cloned MIC sequences in hybridization experiments with DNA obtained from MIC or MAC at various stages and states of differentiation to find out: (i) when alterations occur during the life cycle of the MAC; (ii) whether they occur randomly; (iii) how the MIC sequences being altered are distributed on MIC chromosomes; (iv) whether the sequences being altered are transcribed; (v) which processes cause genome alterations; (vi) what sequences are associated with these processes. First, we will focus on special kinds of sequences. Then, we will attempt to isolate a specific gene which codes for a protein. Our methodology includes cell cloning, gene cloning, chromosome mapping, restriction mapping, analysis of genomic DNA blots with specific probes, electron microscopy, DNA sequencing, and other biochemical procedures. These studies should contribute towards understanding how alterations in DNA molecules occur in normal cells of eukaryotic organisms during development and differentiation.