Mutations affecting cell division in Tetrahymena pyriformis. I. Selection and genetic analysis.
Mutations affecting cell division in Tetrahymena pyriformis. I. Selection and genetic analysis.
复制标题
影响梨形四膜虫细胞分裂的突变。
DOI：
10.1093/genetics/83.3.489
复制
发表时间：
1976
期刊：
影响因子：
3.3
通讯作者：
E. Nelsen
中科院分区：
文献类型：
--
作者：
J. Frankel;L. Jenkins;F. P. Doerder;E. Nelsen
14亚硝基胍诱导的突变，带来了温度敏感的形态异常导致细胞分裂的特定影响已被分离为杂合表型突变体在四膜虫梨形syngen 1。遗传分析表明，所有的单基因隐性。详细分析的突变等位基因之一的分配的动力学揭示了一个率（0.0104纯线每分裂）与以前观察到的在该生物体中的其他位点一致。突变分为6个互补组（mo 1，mo 2，mo 3，mo 6，mo 8和mo 12）。mo 2的纯合子是无条件表达的，而mo 1、mo 6、mo 8和mo 12的所有等位基因对分裂停滞都是热敏的。在mo 3位点上，两个等位基因是热敏感的，一个是主要冷敏感的，而两个是热和冷敏感。不同mo 3等位基因的三种组合中有两种显示表达条件的常规孟德尔分离。mo 1、mo 3、mo 8和mo 12的不同等位基因在限制性温度下的迁移率也存在差异。尽管这些差异涉及表达，异常表型本身是基因座特异性和独特的;在一个情况下（mo 1a和mo 1b），其中两个等位基因表现出有点不同的表型，它们之间的F1是中间的。一个额外的隐性突变（fat 1）导致细胞周期的无条件延长，在限制性温度下细胞分裂的一些停滞。这些发现表明，选择杂合子进行表型分类可以是一种有效的方法，获得大量的所需的一类温度敏感性突变的T。梨形。
Fourteen nitrosoguanidine-induced mutations that bring about temperature-sensitive morphological abnormalities resulting from a specific effect on cell division have been isolated as heterozygous phenotypic assortants in Tetrahymena pyriformis syngen 1. Genetic analysis revealed all to be single-gene recessives. Detailed analysis of the kinetics of assortment for one of the mutated alleles revealed a rate (0.0104 pure lines per fission) consistent with that previously observed at other loci in this organism. The mutations fall into six complementation groups (mo1, mo2, mo3, mo6, mo8, and mo12). Homozygotes of mo2 are unconditionally expresed, while all alleles of mo1, mo6, mo8, and mo12 are heat sensitive for division arrest. At the mo3 locus two alleles are heat senstivie, one is primarily cold sensitive, while two are sensitive to both heat and cold. Two out of three combinations of different mo3 alleles show conventional Mendelian segregation of conditions of expression. Different alleles of mo1, mo3, mo8, and mo12 also manifest differences in penetrance at the restrictive temperature. Despite these differences involving expression, the abnormal phenotypes themselves are locus-specific and distinctive; in the one case (mo1a and mo1b) in which two alleles manifest somewhat different phenotypes, the F1 between them is intermediate. One additional recessive mutation (fat1) brings about a nonconditional lengthening of the cell cycle, with some arrest of cell division at the restrictive temperature. These findings demonstrate that selection of heterozygotes undergoing phenotypic assortment can be an effective method for obtaining substantial numbers of a desired class of temperature-sensitive mutations in T. pyriformis.