Non-Mendelian inheritance of macronuclear mutations is gene specific in Paramecium tetraurelia.
Non-Mendelian inheritance of macronuclear mutations is gene specific in Paramecium tetraurelia.
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大核突变的非孟德尔遗传在草履虫中具有基因特异性。
DOI：
10.1128/mcb.14.4.2479-2484.1994
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发表时间：
1994
影响因子：
5.3
通讯作者：
Forney,JD
中科院分区：
文献类型：
--
作者：
Scott,JM;Mikami,K;Leeck,CL;Forney,JD
四脲草履虫含有两种类型的细胞核，二倍体大芽微核和大的转录活性大核。大核基因组是在有性生殖过程中由微核DNA形成的。以前的研究表明，在新的大核形成过程中，A型可变表面蛋白基因的加工依赖于旧大核中A基因的存在。目前尚不清楚这是控制草履虫大核基因组形成的一般特征还是A位点的独特特征。使用微核移植，我们已经构建了一个菌株，具有野生型微核，但具有大核缺失的A型和B型表面蛋白基因。有性生殖后，A基因和B基因都不会整合到新的大核中。用B基因对该菌株进行大核转化，在形成下一个大核后挽救了B基因缺失，但对A基因缺失没有影响。类似地，用A基因的转化显示对A而不是B的基因特异性拯救。旧大核对新大核加工的影响导致两个大核缺失的非孟德尔遗传模式。来自野生型接合子的后代都是野生型，而来自A-B接合子的后代是突变体。这种A-B非孟德尔突变体的特征表明，大核DNA加工的调节是基因特异性的，我们的结果揭示了这种类型的调节影响草履虫基因组许多区域的可能性。
Paramecium tetraureliacontains two types of nuclei, a diploid germinal micronucleus and a large transcriptionally active macronucleus. The macronuclear genome is formed from the micronuclear DNA during sexual reproduction. Previous studies have shown that the processing of the A-type variable surface protein gene during formation of a new macronucleus is dependent on the presence of the A gene in the old macronucleus. It is not clear if this is a general feature that controls the formation of theParameciummacronuclear genome or a unique feature of the A locus. Using micronuclear transplantation, we have constructed a strain that has a wild-type micronucleus but has macronuclear deletions of the A- and B-type surface protein genes. Neither the A nor the B gene is incorporated into the new macronucleus after sexual reproduction. Macronuclear transformation of this strain with the B gene rescues the B-gene deletion after formation of the next macronucleus but has not effect on the A deletion. Similarly, transformation with the A gene shows gene-specific rescue for A but not B. The effect of the old macronucleus on the processing of the new macronucleus results in a pattern of non-Mendelian inheritance of both macronuclear deletions. Progeny from the wild-type exconjugant are all wild type, and progeny from the A-B-exconjugant are mutant. The features of this A-B-non-Mendelian mutant demonstrate that the regulation of macronuclear DNA processing is gene specific, and our results open the possibility that this type of regulation affects many regions of theParameciumgenome.