Fleig U, Sen-Gupta M, Hegemann J H
Institut fur Mikrobiologie und Molekularbiologie, Universitat Giessen, Germany. Ursula.
Mol Cell Biol. 1996 Nov;16(11):6169-77. doi: 10.1128/MCB.16.11.6169.
By a screen designed to isolate new fission yeast genes required for chromosome segregation, we have identified mal2+. The conditionally lethal mal2-1 allele gives rise to increased loss of a nonessential minichromosome at the permissive temperature and leads to severe missegregation of the chromosomes at the nonpermissive temperature. Cloning by complementation and subsequent sequence analysis revealed that mal2 is a novel protein with a mass of 34 kDa. Cells containing a mal2 null allele were inviable, indicating that mal2+ is an essential gene. Fusion of mal2 protein to the green fluorescent protein (GFP) showed that mal2 was predominantly localized in the nucleus. Sensitivity to microtubule-destabilizing drugs and strong genetic interactions with alpha1-tubulin suggest an interaction of the mal2 protein with the microtubule system. Spindle formation and elongation were not detectably affected in the mal2-1 mutant as determined by indirect immunofluorescence. However, anomalous chromosome movement on the spindle leading to aberrant distribution of the chromosomal material was observed.
通过一个旨在分离染色体分离所需的新裂殖酵母基因的筛选，我们鉴定出了mal2+。条件致死性的mal2-1等位基因在允许温度下会导致非必需小染色体的丢失增加，并在非允许温度下导致染色体的严重错配。通过互补克隆和随后的序列分析表明，mal2是一种新的蛋白质，质量为34 kDa。含有mal2无效等位基因的细胞无法存活，表明mal2+是一个必需基因。将mal2蛋白与绿色荧光蛋白（GFP）融合表明，mal2主要定位于细胞核。对微管破坏药物的敏感性以及与α1-微管蛋白的强遗传相互作用表明mal2蛋白与微管系统相互作用。通过间接免疫荧光法测定，mal2-1突变体中的纺锤体形成和伸长没有明显受到影响。然而，观察到纺锤体上染色体的异常移动导致染色体物质的异常分布。
