Conserved piRNA expression from a distinct set of piRNA cluster loci in eutherian mammals

The Piwi pathway is deeply conserved amongst animals because one of its essential functions is to repress transposons. However, many Piwi-interacting RNAs (piRNAs) do not base-pair to transposons and remain mysterious in their targeting function. The sheer number of piRNA cluster (piC) loci in animal genomes and infrequent piRNA sequence conservation also present challenges in determining which piC loci are most important for development. To address this question, we determined the piRNA expression patterns of piC loci across a wide phylogenetic spectrum of animals, and reveal that most genic and intergenic piC loci evolve rapidly in their capacity to generate piRNAs, regardless of known transposon silencing function. Surprisingly, we also uncovered a distinct set of piC loci with piRNA expression conserved deeply in Eutherian mammals. We name these loci Eutherian-Conserved piRNA cluster (ECpiC) loci. Supporting the hypothesis that conservation of piRNA expression across ~100 million years of Eutherian evolution implies function, we determined that one ECpiC locus generates abundant piRNAs antisense to the STOX1 transcript, a gene clinically associated with preeclampsia. Furthermore, we confirmed reduced piRNAs in existing mouse mutations at ECpiC-Asb1 and -Cbl, which also display spermatogenic defects. The Asb1 mutant testes with strongly reduced Asb1 piRNAs also exhibit up-regulated gene expression profiles. These data indicate ECpiC loci may be specially adapted to support Eutherian reproduction.Gung-wei Chirn, Reazur Rahman, Yuliya A. Sytnikova, Jessica A. Matts, Mei Zeng ... Benjamin T. Kile ... et al

The discovery, distribution, and evolution of viruses associated with drosophila melanogaster

Drosophila melanogaster is a valuable invertebrate model for viral infection and antiviral immunity, and is a focus for studies of insect-virus coevolution. Here we use a metagenomic approach to identify more than 20 previously undetected RNA viruses and a DNA virus associated with wild D. melanogaster. These viruses not only include distant relatives of known insect pathogens, but also novel groups of insect-infecting viruses. By sequencing virus-derived small RNAs we show that the viruses represent active infections of Drosophila. We find that the RNA viruses differ in the number and properties of their small RNAs, and we detect both siRNAs and a novel miRNA from the DNA virus. Analysis of small RNAs also allows us to identify putative viral sequences that lack detectable sequence similarity to known viruses. By surveying >2000 individually collected wild adult Drosophila we show that more than 30% of D. melanogaster carry a detectable virus, and more than 6% carry multiple viruses. However, despite a high prevalence of the Wolbachia endosymbiont—which is known to be protective against virus infections in Drosophila—we were unable to detect any relationship between the presence of Wolbachia and the presence of any virus. Using publicly available RNA-seq datasets we show that the community of viruses in Drosophila laboratories is very different from that seen in the wild, but that some of the newly discovered viruses are nevertheless widespread in laboratory lines and are ubiquitous in cell culture. By sequencing viruses from individual wild-collected flies we show that some viruses are shared between D. melanogaster and D. simulans. Our results provide an essential evolutionary and ecological context for host-virus interaction in Drosophila, and the newly reported viral sequences will help develop D. melanogaster further as a model for molecular and evolutionary virus research

Морфологические изменения в ткани яичника при апоплексии яичника со средним и большим объемом внутрибрюшного кровотечения

Было проанализировано 36 клинических случаев апоплексии яичников у женщин репродуктивного возраста. В зависимости от объема внутрибрюшного кровотечения больные были поделены на две группы: до 500,0 мл и свыше 500,0 мл. Установлено, что: апоплексия желтого тела яичника при среднем объеме внутрибрюшного кровотечения чаще происходила в стадии расцвета желтого тела; апоплексия желтого тела яичника при большом объеме внутрибрюшного кровотечения чаще происходила в стадии регресса желтого тела; наиболее выраженные изменения в сосудах артериального типа чаще встречались при апоплексия желтого тела яичника с большим объемом внутрибрюшного кровотечения; варикозно измененные сосуды венозного типа с признаками тромбообразования чаще встречались при апоплексия желтого тела яичника с большим объемом внутрибрюшного кровотечения.36 clinical cases of apoplexy of ovaries were analysed for the women of fertil age. Patients were divided in two groups depending on volume of the intraabdominal bleeding to 500,0 ml and over 500,0 ml. It is set that: the apoplexy of corpus luteum of ovary at the middle volume of the intraabdominal bleeding more frequent took place in the mature corpus luteum ; the apoplexy of corpus luteum of ovary at the large volume of the intraabdominal bleeding more frequent took place in the stage of regress of corpus luteum ; the most expressed changes in the vessels of arterial type more frequent met at apoplexy of corpus luteum of ovary with the large volume of the intraabdominal bleeding; the varicose changies of venous type vessels with the signs of trombosies more frequent met at apoplexy of corpus luteum of ovary with the large volume of the intraabdominal bleeding

iCLIP of the PIWI Protein Aubergine in Drosophila Embryos.

International audiencePiwi-interacting RNAs (piRNAs) are a class of small noncoding RNAs bound to specific Argonaute proteins, the PIWI proteins. piRNAs target mRNAs by complementarity to silence them; they play an important role in the repression of transposable elements in the germ line of many species. piRNAs and PIWI proteins are also involved in diverse biological processes through their role in the regulation of cellular mRNAs. In the Drosophila embryo, they contribute to the maternal mRNA decay occurring during the maternal-to-zygotic transition. CLIP (UV cross-linking and immunoprecipitation) techniques have been used to identify target mRNAs of Argonaute proteins. Here we describe the iCLIP (individual-nucleotide resolution CLIP) protocol that we have adapted for the PIWI protein Aubergine in Drosophila embryos