tailieunhanh - Báo cáo y học: " Epigenetic transmission of piRNAs through the female germline"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Minireview cung cấp cho các bạn kiến thức về ngành y đề tài: Epigenetic transmission of piRNAs through the female germline. | Minireview Epigenetic transmission of piRNAs through the female germline Sergey Shpiz and Alla Kalmykova Address Institute of Molecular Genetics Russian Academy of Sciences Kurchatov Square 2 Moscow 123182 Russia. Correspondence Alla Kalmykova. Email allakalm@ Published 9 February 2009 Genome Biology 2009 10 208 doi gb-2009-10-2-208 The electronic version of this article is the complete one and can be found online at http 2009 10 2 208 2009 BioMed Central Ltd Abstract In Drosophila small RNAs bound to Piwi proteins are epigenetic factors transmitted from the mother to the progeny germline. This ensures immunization of progeny against transposable elements. The silencing of mobile elements in germ cells depends on a distinct class of RNAs the 24-to-30 nucleotides long Piwi-interacting RNAs piRNAs which are associated with Argonaute proteins of the Piwi subfamily 1 2 . These small RNAs guide the cleavage of complementary RNA or target DNA for methylation and protect the germline against mutations caused by active transposons 2-4 . In Drosophila the three Piwi proteins expressed in the germline are Piwi Aubergine Aub and Argonaute3 Ago3 . Work from the laboratory of Gregory Hannon Brennecke et al. 5 published recently in Science now provides evidence that piRNAs bound to Piwi proteins serve as epigenetic factors that are transmitted through the maternal germline. By piRNA sequencing Hannon and colleagues show that the maternally deposited piRNAs loaded onto Piwi proteins affect transposon suppression in a heritable fashion and that these piRNAs can serve as maternal suppressors of hybrid dysgenesis. This study explains the nature of maternal effects that were noticed long ago in crosses between Drosophila strains that differ in the presence of particular transposable elements the so-called dysgenic crosses. Hybrid dysgenesis is observed in the female progeny of crosses between males that harbor certain active transposable elements .