Identification of Mouse piRNA Pathway Components Using Anti-MIWI2 Antibodies

SUMMARYPachytene piRNAs, which comprise >80% of small RNAs in the adult mouse testis, have been proposed to bind and regulate target RNAs like miRNAs, cleave targets like siRNAs, or lack biological function altogether. Although piRNA pathway protein mutants are male sterile, no biological function has been identified for any mammalian piRNA-producing locus. Here, we report that males lacking piRNAs from a conserved mouse pachytene piRNA locus on chromosome 6 (pi6) produce sperm with defects in capacitation and egg fertilization. Moreover, heterozygous embryos sired bypi6−/−fathers show reduced viability in utero. Molecular analyses suggest thatpi6piRNAs repress gene expression by cleaving mRNAs encoding proteins required for sperm function.pi6also participates in a network of piRNA-piRNA precursor interactions that initiate piRNA production from a second piRNA locus on chromosome 10 as well aspi6itself. Our data establish a direct role for pachytene piRNAs in spermiogenesis and embryo viability.HighlightsNormal male mouse fertility and spermiogenesis require piRNAs from thepi6locusSperm capacitation and binding to the zona pellucida of the egg requirepi6piRNAsHeterozygous embryos sired bypi6−/−fathers show reduced viability in uteroDefects inpi6mutant sperm reflect changes in the abundance of specific mRNAs.

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Intergenerational metabolic priming by sperm piRNAs

10.1101/2021.03.29.436592 ◽

2021 ◽

Author(s):

Adelheid Lempradl ◽

Unn Kugelberg ◽

Mary Iconomou ◽

Ian Beddows ◽

Daniel Nätt ◽

...

Keyword(s):

Small Rna ◽

Small Rnas ◽

Target Gene ◽

Epigenetic Inheritance ◽

Mature Sperm ◽

Transcriptional Reprogramming ◽

Complementary Sequences ◽

Specific Manner ◽

Dietary Sugar ◽

Pirna Pathway

Preconception parental environment can reproducibly program offspring phenotype without altering the DNA sequence, yet the mechanisms underpinning this epigenetic inheritance remains elusive. Here, we demonstrate the existence of an intact piRNA-pathway in mature Drosophila sperm and show that pathway modulation alters offspring gene transcription in a sequence-specific manner. We map a dynamic small RNA content in developing sperm and find that the mature sperm carry a highly distinct small RNA cargo. By biochemical pulldown, we identify a small RNA subset bound directly to piwi protein. And, we show that piRNA-pathway controlled sperm small RNAs are linked to target gene repression in offspring. Critically, we find that full piRNA-pathway dosage is necessary for the intergenerational metabolic and transcriptional reprogramming events triggered by high paternal dietary sugar. These data provide a direct link between regulation of endogenous mature sperm small RNAs and transcriptional programming of complementary sequences in offspring. Thus, we identify a novel mediator of paternal intergenerational epigenetic inheritance.

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Golden hamster piRNAs are necessary for early embryonic development and establishment of spermatogonia

10.1101/2021.01.27.428513 ◽

2021 ◽

Author(s):

Zuzana Loubalova ◽

Helena Fulka ◽

Filip Horvat ◽

Josef Pasulka ◽

Radek Malik ◽

...

Keyword(s):

Embryonic Development ◽

Golden Hamster ◽

Developmental Competence ◽

Early Embryonic Development ◽

Spermatogenic Cells ◽

Adaptive Nature ◽

Pirna Pathway

ABSTRACTPIWI-associated RNAs (piRNAs) support the germline by suppressing retrotransposons and genes. In mice, piRNAs are essential for spermatogenesis but not oogenesis. To test how this applies to other mammals, we deleted Mov10l1 helicase in golden hamster, whose piRNA pathway is configured more similarly to that of other mammals. Mov10l1−/− male hamsters showed impaired establishment of spermatogonia accompanied by transcriptome dysregulation and a surge in MYSERV retrotransposon expression. The rare viable spermatogenic cells showed a meiotic failure phenotype like Mov10l1−/− mice. Female Mov10l1−/− hamsters were sterile due to post-meiotic loss of developmental competence in zygotes. Unique phenotypes of Mov10l1−/− hamsters demonstrate the adaptive nature of piRNA-mediated control of genes and retrotransposons in order to confront emerging genomic threats or acquire new physiological roles.

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Multiple roles of PIWIL1 in mouse neocorticogenesis

10.1101/106070 ◽

2017 ◽

Cited By ~ 6

Author(s):

Barbara Viljetic ◽

Liyang Diao ◽

Jixia Liu ◽

Zeljka Krsnik ◽

Sagara H.R. Wijeratne ◽

...

Keyword(s):

Cell Cycle ◽

Small Rna ◽

Radial Glia ◽

Multiple Roles ◽

Small Rna Sequencing ◽

Knock Out ◽

Deep Layers ◽

Pirna Pathway ◽

The Brain

AbstractPIWI-interacting RNAs (piRNAs) and their associated PIWI proteins play an important role in repressing transposable elements in animal germlines. However, little is known about the function of PIWI proteins and piRNAs in the developing brain. Here, we investigated the role of an important PIWI family member, Piwi-like protein 1 (Piwil1; also known as Miwi in mouse) in the developing mouse neocortex. Using a Piwil1 knock-out (Piwil1 KO) mouse strain, we found that Piwil1 is essential for several steps of neocorticogenesis, including neocortical cell cycle, neuron migration and dendritogenesis. Piwil1 deletion resulted in increased cell cycle re-entry at embryonic day 17 (E17) when predominantly intracortically projecting neurons are being produced. Prenatal Piwil1 deletion increased the number of Pax6+ radial glia at postnatal day 0 (P0). Furthermore, Piwil1 deletion disrupted migration of Satb2+ neurons within deep layers at E17, P0 and P7. Satb2+ neurons showed increased co-localization with Bcl11b (also known as Ctip2), marker of subcortically projecting neurons. Piwil1 knockouts had disrupted neocortical circuitry represented by thinning of the corpus callosum and altered dendritogenesis. We further investigated if Piwil1 deletion disrupted expression levels of neocortical piRNAs by small RNA-sequencing in neocortex. We did not find differential expression of piRNAs in the neocortices of Piwil1 KO, while differences were observed in other Piwil1 KO tissues. This result suggests that Piwil1 may act independently of piRNAs and have novel roles in higher cognitive centers, such as neocortex. In addition, we report a screen of piRNAs derived from tRNA fragments in developing neocortices. Our result is the first report of selective subsets of piRNAs and tRNA fragments in developing prenatal neocortices and helps clarify some outstanding questions about the role of the piRNA pathway in the brain.

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