Change - Piwi-interacting RNA

Created on Nov. 30, 2012, 11:37 p.m. by Hevok & updated on Dec. 1, 2012, 12:47 a.m. by Hevok

RNA interference can be heritable, which means that it can have transgenerational effects [Burton et al. 2011]. Responsible for this appears to be piwi-interacting RNAs (piRNAs) [Brennecke et al. 2008; Grentzinger et al. 2012]. piRNAs are slightly longer than microRNAs and associated with RNA-protein complexes, mediated by the binding to Piwi proteins. piRNAs represent a much bigger class of non-coding RNA than microRNAs. piRNAs are associated with gene silencing, most especially at repeat elements like transposons [Aravin et al. 2008]. piRNAs are important in the germline, where they can aid in establishing other epigenetic patterns like DNA methylation and histone modifications. ¶

piRNA cis-regulate DNA-methylation. A methylation determining region produces a specialized form of RNA (pit-RNA) that is essential for methylation in cis [Park et al. 2012]. Heritable piRNA appears to direct methylation occurring in mammalian germ cells. Mice lacking certain piRNAs fail to re-methylate properly after the loss of methylation during fertilization [Aravin et al. 2008; Aravin & Bourc'his, 2008; Ashe et al. 2012]. piRNAs cluster at L1 promoter, indicating that they are involved in establishment of DNA methylation. ¶

piRNAs are responsible for inheritance of histone marks in C. elegans, which lack DNA methylation [Burton et al. 2011]. ¶

In C. elegans longevity conferred through deficiencies in H3K4me3 chromatin modifiers ASH-2, WDR5 or SET-2 is inherited transgenerational, which requires the presence of a functioning germline in the descendants [Greer et al. 201
1]. ¶

The expression of piRNA is downregulated during aging in C. elegans [Kato et al. 2011]. ¶

References
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Burton NO, Burkhart KB, Kennedy S. Nuclear RNAi maintains heritable gene silencing in Caenorhabditis elegans. Proc. Natl. Acad. Sci. U.S.A. (2011). ¶

Brennecke J, Malone CD, Aravin AA, Sachidanandam R, Stark A, Hannon GJ. An epigenetic role for maternally inherited piRNAs in transposon silencing. Science. 322(5906), 1387–1392 (2008). ¶

Grentzinger T, Armenise C, Brun C, et al. piRNA-mediated transgenerational inheritance of an acquired trait. Genome Res. (2012). ¶

Aravin AA, Sachidanandam R, Bourc'his D, et al. A piRNA pathway primed by individual transposons is linked to de novo DNA methylation in mice. Mol. Cell. 31(6), 785–799 (2008). ¶

Park YJ, Herman H, Gao Y, et al. Sequences sufficient for programming imprinted germline DNA methylation defined. PLoS ONE. 7(3), e33024 (2012). ¶

Aravin AA, Bourc'his D. Small RNA guides for de novo DNA methylation in mammalian germ cells. Genes Dev. 22(8), 970–975 (2008). ¶

Ashe A, Sapetschnig A, Weick E-M, et al. piRNAs Can Trigger a Multigenerational Epigenetic Memory in the Germline of C.elegans. Cell. 1–12 (2012). ¶

Burton NO, Burkhart KB, Kennedy S. Nuclear RNAi maintains heritable gene silencing in Caenorhabditis elegans. Proc. Natl. Acad. Sci. U.S.A. (2011). ¶

Greer EL, Maures TJ, Ucar D, Hauswirth AG, Mancini E, Lim JP, Benayoun BA, Shi Y, Brunet A (2011) Transgenerational epigenetic inheritance of longevity in Caenorhabditis elegans. Nature 479: 365-71. ¶

Kato M, Chen X, Inukai S, Zhao H, Slack FJ. Age-associated changes in expression of small, noncoding RNAs, including microRNAs, in C. elegans. RNA. 17(10), 1804–1820 (2011). ¶


Comment: Corrected reference year of Greer et al.

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