1. 南芥是一，泛用於基生物的植物物。由於多用途之象的助，美冷泉港室(CSHL)的科家，在已挖掘出一，有助於控制程的秘密。
Arabidopsis thaliana is a plant species widely used to make fundamental biological discoveries. With the help of this versatile test subject, CSHL scientists have now dug up the secrets of a process that helps control inheritance.
When organisms pass their genes on to future generations, they include more than the code spelled out in DNA. Some also pass along chemical markers that instruct cells how to use that code. The passage of these markers to future generations is known as epigenetic inheritance. It’s particularly common in plants. So, significant findings here may have implications for agriculture, food supplies, and the environment.
生物其基因後代，它不包含DNA中，拼出的密。有些也，指令胞如何使用那密的化。此些後代的移，被通成(表)的。在植物中，特常。因此，在的重大，可能、食供及境具有多意涵。
2. 此影片示了，在胞分裂程中，DNA甲基化少I (/span>DDM1(色)：Decreased DNA Methylation I。是一，促DNA甲基化之核小重塑因子的植物基因)的作情。染色，DDM1著於染色上，添加重要化做好。之後，胞一分二，DDM1退出，而另一蛋白H3.3(色)染色合，防止添加量。 (原文短片)
This video shows DDM1 (green) at work during cell division. As chromosomes are duplicated, DDM1 latches onto chromosomes to allow for vital chemical markers to be tacked on. Then, as the cell divides in two, DDM1 exits, and another protein, H3.3 (red), binds to chromosomes to prevent excess markers from being added.
Cold Spring Harbor Laboratory (CSHL) Professors and HHMI Investigators Rob Martienssen and Leemor Joshua-Tor have been researching how plants pass along the markers that keep transposons inactive. Transposons are also known as jumping genes. When switched on, they can move around and disrupt other genes. To silence them and protect the genome, cells add regulatory marks to specific DNA sites. This process is called methylation.
冷泉港室(CSHL)教授及霍德休斯研究所(HHMI：Howard Hughes Medical Institute)研究，Rob Martienssen及Leemor Joshua-Tor 一直行研究，植物如何，保持也被通跳基因之位子不活的。被打，它能四移其他基因。了使它默及保基因，胞性，添加到特定的DNA位。此程被甲基化。
Martienssen and Joshua-Tor have now shown how protein DDM1 makes way for the enzyme that places these marks on new DNA strands. Plant cells need DDM1 because their DNA is tightly packaged. To keep their genomes compact and orderly, cells wrap their DNA around packing proteins called histones.
目前，Martienssen及Joshua-Tor已了，DDM1蛋白如何，在新DNA股上，放置些的酵素路。植物胞需要DDM1，因其DNA被密封包。了保持其基因密有序，胞其DNA於，被蛋白的封包蛋白周遭。
“But that blocks access to the DNA for all sorts of important enzymes,” Martienssen explains. Before methylation can occur, “you have to remove or slide the histones out of the way.”
Martienssen解：「不，各重要酵素而言，那阻了接DNA的途。」在甲基化能生之前，「必移除或使此蛋白滑此途。」
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Martienssen and former CSHL colleague Eric Richards first discovered DDM1 30 years ago. Since then, researchers have learned it slides DNA along its packing proteins to expose sites needing methylation. Martienssen likens the movement to a yo-yo gliding along a string. The histones “can move up and down the DNA, exposing parts of the DNA at a time, but never falling off,” he explains.
30年前，Martienssen及前CSHL同僚Eric Richards，首度DDM1。打那起，研究人已得悉，它沿著其封包蛋白滑DNA，暴露需要甲基化的位。Martienssen此移比喻，沿著子滑的溜溜球。他解：「蛋白能上、下移DNA，一次暴露部分DNA，不不分。」
Through genetic and biochemical experiments, Martienssen pinpointed the exact histones DDM1 displaces. Joshua-Tor used cryo-electron microscopy to capture detailed images of the enzyme interacting with DNA and associated packing proteins. They were able to see how DDM1 grabs onto particular histones to remodel packaged DNA. “An unexpected bond that ties DDM1 together turned out to correspond to the first mutation found all those years ago,” Joshua-Tor says.
透及生化，Martienssen精找出了，DDM1移的切蛋白。Joshua-Tor使用了低子微，捕捉DNA及相包蛋白相互作用之酶的像。他能看到DDM1，如何抓住特定蛋白，重新塑造封包的DNA。Joshua-Tor宣：「一DDM1在一起之意想不到的束物，被相於那些年前，的第一突。」
3. 此卡通模型首度明了，在胞分裂程中，DDM1蛋白(紫色)在何及如何抓牢DNA(米色)。
This cartoon model illustrates, for the first time, where and how the DDM1 protein (purple) grips onto DNA (beige) during cell division.
The experiments also revealed how DDM1’s affinity for certain histones preserves epigenetic controls across generations. The team showed that a histone found only in pollen is resistant to DDM1 and acts as a placeholder during cell division. “It remembers where the histone was during plant development and retains that memory into the next generation,” Martienssen says.
此些也揭露了，DDM1某些蛋白的和性，如何在跨世代，保存成的控制能耐。了，在花粉中的蛋白， DDM1具抵抗力，且在胞分裂程中，充一位物(可被特定物取代之物)。Martienssen宣：「它住，在植物育程中，蛋白的位置，那保留到下一代。」
Plants may not be alone here. Humans also depend on DDM1-like proteins to maintain DNA methylation. The new discovery may help explain how those proteins keep our genomes functional and intact.
在，植物可能不孤。人也依DDM1的蛋白，持DNA 甲基化。此新可能有助於解，那些蛋白如何保持咱基因的功能及完整性。
址：https://www.cshl.edu/how-plants-pass-down-genetic-memories/
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