The tubB alpha-tubulin gene is essential for sexual development in Aspergillus nidulans.
The tubB alpha-tubulin gene is essential for sexual development in Aspergillus nidulans.
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DOI：
10.1101/gad.5.11.2014
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发表时间：
1991-11
影响因子：
10.5
通讯作者：
K. E. Kirk;N. Morris
中科院分区：
文献类型：
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作者：
K. E. Kirk;N. Morris
丝状真菌尼杜拉曲霉有两个编码α-微管蛋白的基因，tuba和tubb。对tuba基因的突变分析表明，tuba基因是有丝分裂和核迁移所必需的。在这项研究中，我们删除了Tubb基因，用一个可选择的标记取代了它，并将这个新的等位基因命名为Tubb Delta。结果表明，Tubb基因不是营养生长或无性繁殖所必需的，也不是启动或早期性分化所必需的。然而，Tubb的缺失完全阻止了子囊孢子的发生，因为Tubb Delta菌株在自交时不产生有性孢子。当这些菌株与Tubb+菌株杂交时会产生活的子囊孢子，这表明Tubb Delta突变是隐性的。我们研究了野生型菌株和Tubb突变体的性发育细胞学，并观察到Tubb三角洲。菌株正常发育到子囊形成阶段。然而，在Tubb三角洲ASCUS中只观察到一个核团，这表明要么两个合子单倍体核在核配子中受阻，要么核受精发生，但由此产生的二倍体核在减数分裂I中受阻。
The filamentous fungus Aspergillus nidulans has two genes encoding alpha-tubulin, tubA and tubB. Mutational analysis of tubA has demonstrated that the tubA gene is essential for mitosis and nuclear migration. In this study we have deleted the tubB gene by replacing it with a selectable marker and have named this new allele tubB delta. The results demonstrate that the tubB gene is not required for vegetative growth or asexual reproduction, nor is it required for the initiation or early stages of sexual differentiation. Deletion of tubB, however, completely prevents ascosporogenesis, because tubB delta strains produce no sexual spores when self-crossed. These strains produce viable ascospores when outcrossed to tubB+ strains, indicating that the tubB delta mutation is recessive. We have studied the cytology of sexual development in wild-type strains and in the tubB mutant and have observed that tubB delta. strains develop normally to the stage of ascus formation. However, only a single nuclear mass is observed in the tubB delta ascus, indicating that either the two zygotic haploid nuclei are blocked in karyogamy or that karyogamy occurs but the resulting diploid nucleus is subsequently blocked in meiosis I.