小柯机器人

奥地利科学院分子生物技术研究所Alejandro Burga课题组发现，自私冲突是RNA介导的亲源效应的基础。相关论文于2024年3月6日在线发表在《自然》杂志上。

研究人员表示，基因组印记，即母本基因组和父本基因组的非等同性，是在许多植物和哺乳动物物种中独立演化的一个关键过程。根据亲缘关系理论，印记是冲突性选择力作用于不同表达的亲代等位基因的必然结果。然而，人们对这些表观遗传差异是如何演化的却知之甚少。

研究人员报告了对基因表达亲源效应的鉴定和分子剖析，这可能有助于澄清这一基本问题。毒素解毒元件（TA）是一种自私的元件，它通过毒害非载体个体在种群中传播。在两个Caenorhabditis tropicalis野生分离株之间的互交中，研究人员发现slow-1/grow-1 TA在父系遗传时具有特异性的非活性。这种亲源效应源于PIWI-interacting RNA（piRNA）宿主防御途径对slow-1毒素的转录抑制。这种抑制需要PIWI Argonaute和SET-32组蛋白甲基转移酶的活性，并通过小RNA进行跨代遗传。

值得注意的是，当slow-1/grow-1为母系遗传时，其母源mRNA的翻译依赖性作用会阻止slow-1的抑制作用。也就是说，加载到卵子中的slow-1转录本而非SLOW-1蛋白是抵消piRNA介导的抑制所必要且充分的。这些研究结果表明，亲源效应可以通过共同采用piRNA途径来演化，并阻碍需要性才能传播的自私基因的扩散。

附：英文原文

Title: Selfish conflict underlies RNA-mediated parent-of-origin effects

Author: Pliota, Pinelopi, Marvanova, Hana, Koreshova, Alevtina, Kaufman, Yotam, Tikanova, Polina, Krogull, Daniel, Hagmller, Andreas, Widen, Sonya A., Handler, Dominik, Gokcezade, Joseph, Duchek, Peter, Brennecke, Julius, Ben-David, Eyal, Burga, Alejandro

Issue&Volume: 2024-03-06

Abstract: Genomic imprinting—the non-equivalence of maternal and paternal genomes—is a critical process that has evolved independently in many plant and mammalian species1,2. According to kinship theory, imprinting is the inevitable consequence of conflictive selective forces acting on differentially expressed parental alleles3,4. Yet, how these epigenetic differences evolve in the first place is poorly understood3,5,6. Here we report the identification and molecular dissection of a parent-of-origin effect on gene expression that might help to clarify this fundamental question. Toxin-antidote elements (TAs) are selfish elements that spread in populations by poisoning non-carrier individuals7,8,9. In reciprocal crosses between two Caenorhabditis tropicalis wild isolates, we found that the slow-1/grow-1 TA is specifically inactive when paternally inherited. This parent-of-origin effect stems from transcriptional repression of the slow-1 toxin by the PIWI-interacting RNA (piRNA) host defence pathway. The repression requires PIWI Argonaute and SET-32 histone methyltransferase activities and is transgenerationally inherited via small RNAs. Remarkably, when slow-1/grow-1 is maternally inherited, slow-1 repression is halted by a translation-independent role of its maternal mRNA. That is, slow-1 transcripts loaded into eggs—but not SLOW-1 protein—are necessary and sufficient to counteract piRNA-mediated repression. Our findings show that parent-of-origin effects can evolve by co-option of the piRNA pathway and hinder the spread of selfish genes that require sex for their propagation.

DOI: 10.1038/s41586-024-07155-z

Source: https://www.nature.com/articles/s41586-024-07155-z

Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
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