Our understanding of the biological functions of small non-coding RNAs has been fostered by the analysis of genetic deletions of individual microRNAs (miRNAs) in mammals. These studies show that miRNAs are key regulators of animal development and are potential human disease loci.

Small non-coding RNAs in animal development

Small non-coding RNAs (sncRNAs) are potential vectors at the interface between genes and environment. We found that traumatic stress in early life altered mouse microRNA (miRNA) expression, and behavioral and metabolic responses in the progeny. Injection of sperm RNAs from traumatized males into fertilized wild-type oocytes reproduced the behavioral and metabolic alterations in the resulting offspring.

/pdf/implication-of-sperm-rnas-in-transgenerational-inheritance-2foybd5oaz.pdf

Implication of sperm RNAs in transgenerational inheritance of the effects of early trauma in mice

http://molecular-ethology.biochem.s.u-tokyo.ac.jp/neuro-seminar/ftp-box/piRNA-Aplysia.pdf

A role for neuronal piRNAs in the epigenetic control of memory-related synaptic plasticity.

Several distinct classes of small RNAs, some newly identified, have been discovered to play important regulatory roles in diverse cellular processes. These classes include siRNAs, miRNAs, rasiRNAs and piRNAs. Each class binds to distinct members of the Argonaute/Piwi protein family to form ribonucleoprotein complexes that recognize partially, or nearly perfect, complementary nucleic acid targets, and that mediate a variety of regulatory processes, including transcriptional and post-transcriptional gene silencing. Based on the known relationship of Argonaute/Piwi proteins with distinct classes of small RNAs, we can now predict how many new classes of small RNAs or silencing processes remain to be discovered.

The growing catalog of small RNAs and their association with distinct Argonaute/Piwi family members

Piwi and piRNAs Act Upstream of an Endogenous siRNA Pathway to Suppress Tc3 Transposon Mobility in the Caenorhabditis elegans Germline

The recent discovery of a new class of 30-nucleotide long RNAs in mammalian testes, called PIWI-interacting RNA (piRNA), with similarities to microRNAs and repeat-associated small interfering RNAs (rasiRNAs), has raised puzzling questions regarding their biogenesis and function. We report a comparative analysis of currently available piRNA sequence data from the pachytene stage of mouse spermatogenesis that sheds light on their sequence diversity and mechanism of biogenesis. We conclude that (i) there are at least four times as many piRNAs in mouse testes than currently known; (ii) piRNAs, which originate from long precursor transcripts, are generated by quasi-random enzymatic processing that is guided by a weak sequence signature at the piRNA 5′ends resulting in a large number of distinct sequences; and (iii) many of the piRNA clusters contain inverted repeats segments capable of forming double-strand RNA fold-back segments that may initiate piRNA processing analogous to transposon silencing.

/pdf/computational-analysis-of-mouse-pirna-sequence-and-rw84r1blo2.pdf

Computational analysis of mouse piRNA sequence and biogenesis.

AlignmentViewer is a web-based tool to view and analyze multiple sequence alignments of protein families. The particular strengths of AlignmentViewer include flexible visualization at different scales as well as analysis of conservation patterns and of the distribution of proteins in sequence space. The tool is directly accessible in web browsers without the need for software installation. It can handle protein families with tens of thousands of sequences and is particularly suitable for evolutionary coupling analysis, e.g. via EVcouplings.org.

AlignmentViewer: Sequence Analysis of Large Protein Families.

AlignmentViewer is multiple sequence alignment viewer for protein families with flexible visualization, analysis tools and links to protein family databases. It is directly accessible in web browsers without the need for software installation, as it is implemented in JavaScript, and does not require an internet connection to function. It can handle protein families with tens of thousands of sequences and is particularly suitable for evolutionary coupling analysis, facilitating the computation of protein 3D structures and the detection of functionally constrained interactions.

/pdf/alignmentviewer-sequence-analysis-of-large-protein-families-5g0ryksnl8.pdf

Rob Sheridan

Papers

Computational analysis of mouse piRNA sequence and biogenesis.

AlignmentViewer: Sequence Analysis of Large Protein Families.

AlignmentViewer: Sequence Analysis of Large Protein Families