Nucl. Acids Res.-2011-Teng-7371-9.pdf

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Miwi catalysis is required for piRNA amplification-independent LINE1 transposon silencing
http://www.nature.com/nature/journal/v480/n7376/full/nature10672.html?WT.ec_id=NATURE-20111208

资料:Piwi-interacting RNA (piRNA) is the largest class of small non-coding RNA molecules that is expressed in animal cells.^[1][2] piRNAs form RNA-protein complexes through interactions with piwi proteins. These piRNA complexes have been linked to both epigenetic and post-transcriptional gene silencing of retrotransposons and other genetic elements in germ line cells, particularly those in spermatogenesis ^[3]. They are distinct from microRNA (miRNA) in size (26–31 nt rather than 21–24 nt), lack of sequence conservation, and increased complexity.^[1][2]

It remains unclear how piRNAs are generated, but potential methods have been suggested, and it is certain their biogenesis pathway is distinct from miRNA and siRNA, while rasiRNAs are a piRNA subspecies.^[4]

植物里有没?

The endonuclease activity of Mili fuels piRNA amplification that silences LINE1 elements
http://www.nature.com/nature/journal/v480/n7376/full/nature10547.html?WT.ec_id=NATURE-20111208

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Small RNAs and transposon silencing in plants

Small RNAs and transposon silencing in plants.pdf

该文摘要的第1句:Transposons are highly conserved in plants and have created a symbiotic relationship with the host genome.转座子在植物中是高度保守的,已经和宿主基因组建立了共生关系.当然这里的highly conserved可能还得具体分析.它的功能可能和基因表达调控和逆境中的应急机制有关.好象也容易理解.重复序列中如果包含了顺式调控元件,这为同步调控多个基因提供了方便,当然这仅仅是我的一点想想.另外遭遇逆境的时候,转座子出来活动活动以内部基因组的变化迎接逆境的挑战,也比较好理解,不变可能以为着灭亡,变可能还有一线生机.如果弄清楚了变异的诱导机制,不是在逆境环境中,也许同样能让它发生变化,而变化的方向,可以是认为设定的方向或者经过人为的选择.当功能基因正如火如荼的进行时,不不能忘了还有其它重要的东西.

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转座子可能还和疾病有关系:Retrotransposition is associated with genome instability during chronological aging(http://www.pnas.org/content/108/51/20376.abstract?etoc).这意味着对这方面的投入今后可能迅速和持续的增加,有投入一般情况是会有产出的.所以揭开她的神秘面纱的时候,可能已经不远了.

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Mobilization of giant piggyBac transposons in the mouse genome (http://nar.oxfordjournals.org/content/39/22/e148.abstract?etoc).转座子可以作为1中运载工具.装着100kb的DNA片段在基因组中跑.累不累啊

Transposon Ac/Ds-induced chromosomal rearrangements at the rice OsRLG5 locus(http://nar.oxfordjournals.org/content/39/22/e149.abstract?etoc)除了插入突变外rearrangement也是一种效应.所以Ac/Ds系统产生的突变和T-DNA插入产生的突变,在机理上是有差异的.