The persistence of maternal inheritance in Chlamydomonas despite hypomethylation of chloroplast DNA induced by inhibitors.
The persistence of maternal inheritance in Chlamydomonas despite hypomethylation of chloroplast DNA induced by inhibitors.
复制标题
尽管抑制剂诱导叶绿体 DNA 低甲基化，但衣藻中母系遗传的持续存在。
DOI：
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发表时间：
1984
影响因子：
11.1
通讯作者：
K. Chiang
中科院分区：
文献类型：
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作者：
T. Feng;K. Chiang
我们使用甲基化抑制剂评估了野生型衣藻配子发生过程中交配型+(mt+)亲本的叶绿体DNA(CpDNA)甲基化程度与该亲本对叶绿体基因的单亲传递直接相关的建议[Sager，R.，Grabowy，C.&Sano，H.(1981)Cell 24，41-47]。高压液相色谱检测发现，cpDNA甲基化在营养生长期处于最低水平，mt+细胞的脱氧胞苷甲基化指数(脱氧胞苷甲基化百分率)为0.5，而交配类型减去(mt-)指数至少低3倍。配子发生后cpDNA甲基化的基础水平增加了20多倍，mt+和mt-配子的甲基化指数分别为12.1和4.3。在7小时受精卵阶段检测到另一个显著的增加，导致近一半的总脱氧胞苷残基的甲基化。合子cpDNA甲基化的程度取决于双亲配子cpDNA先前存在的甲基化水平。Hpa II/Msp I酶切图谱和高效液相色谱显示，L-乙硫氨酸和5-氮杂胞苷有效地抑制了配子发生和随后的合子发育过程中的cpDNA甲基化。结合抑制剂的研究，分析了叶绿体基因的传递。这两种抑制剂在特定发育阶段的mt-和mt+细胞中产生不同的甲基化抑制模式。我们的总体结果表明，配子发生过程中特定交配类型和特定配子的甲基化程度与母体传递叶绿体基因的频率无关。
We have used inhibitors of methylation to evaluate the proposal that the extent of methylation of chloroplast DNA ( cpDNA ) of the mating type-plus (mt+) parent occurring during gametogenesis in wild-type Chlamydomonas renhardtii is directly correlated with the uniparental transmission of chloroplast genes by this parent [ Sager , R., Grabowy , C. & Sano , H. (1981) Cell 24, 41-47]. As detected by high-pressure liquid chromatography, the methylation of cpDNA was at its lowest level in the vegetative stage; the mt+ cells had a deoxycytidine methylation index (the percentage of deoxycytidine methylated) of 0.5, while the mating type-minus (mt-) index was lower by at least a factor of 3. This basal level of cpDNA methylation increased more than 20-fold after gametogenesis to give a methylation index of 12.1 and 4.3 for mt+ and mt- gametes, respectively. Another striking increase was detected at the 7-hr-zygote stage, resulting in the methylation of nearly half of the total deoxycytidine residues. The extent of zygotic cpDNA methylation was shown to be dependent on the preexisting methylation level of both parental gametic cpDNAs . L-Ethionine and 5-azacytidine effectively inhibited cpDNA methylation during gametogenesis and ensuing zygotic development as shown by both Hpa II/Msp I digestion patterns and HPLC. The transmission of chloroplast genes was analyzed concomitantly with the inhibitor studies. The two inhibitors produced different patterns of inhibition of methylation in mt- and mt+ cells at a given developmental stage. Our overall results demonstrate that the extent of mating type-specific and gamete-specific methylation during gametogenesis is not correlated with the frequency of maternal transmission of chloroplast genes.