scholarly journals Somatic piRNAs and Transposons are Differentially Expressed Coincident with Skeletal Muscle Atrophy and Programmed Cell Death

2021 ◽  
Vol 12 ◽  
Author(s):  
Junko Tsuji ◽  
Travis Thomson ◽  
Christine Brown ◽  
Subhanita Ghosh ◽  
William E. Theurkauf ◽  
...  

PIWI-interacting RNAs (piRNAs) are small single-stranded RNAs that can repress transposon expression via epigenetic silencing and transcript degradation. They have been identified predominantly in the ovary and testis, where they serve essential roles in transposon silencing in order to protect the integrity of the genome in the germline. The potential expression of piRNAs in somatic cells has been controversial. In the present study we demonstrate the expression of piRNAs derived from both genic and transposon RNAs in the intersegmental muscles (ISMs) from the tobacco hawkmoth Manduca sexta. These piRNAs are abundantly expressed, ∼27 nt long, map antisense to transposons, are oxidation resistant, exhibit a 5’ uridine bias, and amplify via the canonical ping-pong pathway. An RNA-seq analysis demonstrated that 19 piRNA pathway genes are expressed in the ISMs and are developmentally regulated. The abundance of piRNAs does not change when the muscles initiate developmentally-regulated atrophy, but are repressed coincident with the commitment of the muscles undergo programmed cell death at the end of metamorphosis. This change in piRNA expression is correlated with the repression of several retrotransposons and the induction of specific DNA transposons. The developmentally-regulated changes in the expression of piRNAs, piRNA pathway genes, and transposons are all regulated by 20-hydroxyecdysone, the steroid hormone that controls the timing of ISM death. Taken together, these data provide compelling evidence for the existence of piRNA in somatic tissues and suggest that they may play roles in developmental processes such as programmed cell death.

2021 ◽  
Author(s):  
Junko Tsuji ◽  
Travis Thomson ◽  
Christine Brown ◽  
Subhanita Ghosh ◽  
William E. Theurkauf ◽  
...  

AbstractPiWi-interacting RNAs (piRNAs) are small single-stranded RNAs that can repress transposon expression via epigenetic silencing and transcript degradation. They have been identified predominantly in the ovary and testis, where they serve essential roles in transposon silencing in order to protect the integrity of the genome in the germline. The potential expression of piRNAs in somatic cells has been controversial. In the present study we demonstrate the expression of piRNAs derived from both genic and transposon RNAs in the intersegmental muscles (ISMs) from the tobacco hawkmoth Manduca sexta. These piRNAs are abundantly expressed, are ~27 nt long, map antisense to transposons, are oxidation resistant, exhibit a uridine bias at their first nucleotide, and amplify via the canonical ping-pong pathway. An RNA-seq analysis demonstrated that 20 piRNA pathway genes are expressed in the ISMs and are developmentally regulated. The abundance of piRNAs does not change when the muscles initiate developmentally-regulated atrophy, but are repressed when cells become committed to undergo programmed cell death at the end of metamorphosis. This change in piRNA expression is associated with the targeted repression of several retrotransposons and the induction of specific DNA transposons. The developmental changes in the expression of piRNAs, piRNA pathway genes, and transposons are all regulated by 20-hydroxyecdysone, the steroid hormone that controls the timing of ISM death. Taken together, these data provide compelling evidence for the existence of piRNA in somatic tissues and suggest that they may play roles in developmental processes such as programmed cell death.Author SummarypiRNAs are a class of small non-coding RNAs that suppress the expression of transposable elements, parasitic DNA that if reintegrated, can harm the integrity of the host genome. The expression of piRNAs and their associated regulatory proteins has been studied predominantly in germ cells and some stem cells. We have found that they are also expressed in skeletal muscles in the moth Manduca sexta that undergo developmentally-regulated atrophy and programmed cell death at the end of metamorphosis. The expression of transposons becomes deregulated when the muscles become committed to die, which may play a functional role in the demise of the cell by inducing genome damage. piRNA-mediated control of transposons may represent a novel mechanism that contributes to the regulated death of highly differentiated somatic cells.


2020 ◽  
Vol 107 (4) ◽  
pp. 577-586
Author(s):  
Georgia L. Denbigh ◽  
Adrian N. Dauphinee ◽  
Meredith S. Fraser ◽  
Christian R. Lacroix ◽  
Arunika H. L. A. N. Gunawardena

2010 ◽  
Vol 519 (1) ◽  
pp. 34-48 ◽  
Author(s):  
Gyunghee Lee ◽  
Zixing Wang ◽  
Ritika Sehgal ◽  
Chun-Hong Chen ◽  
Keiko Kikuno ◽  
...  

Reproduction ◽  
2017 ◽  
Vol 153 (3) ◽  
pp. 305-318 ◽  
Author(s):  
Stewart Russell ◽  
Mehool Patel ◽  
Graham Gilchrist ◽  
Leanne Stalker ◽  
Daniel Gillis ◽  
...  

PIWI proteins and their associated piRNAs have been the focus of intensive research in the past decade; therefore, their participation in the maintenance of genomic integrity during spermatogenesis has been well established. Recent studies have suggested important roles for the PIWI/piRNA system outside of gametogenesis, based on the presence of piRNAs and PIWI proteins in several somatic tissues, cancers, and the early embryo. Here, we investigated the small RNA complement present in bovine gonads, gametes, and embryos through next-generation sequencing. A distinct piRNA population was present in the testis as expected. However, we also found a large population of slightly shorter, 24–27 nt piRNA-like RNA (pilRNAs) in pools of oocytes and zygotes. These oocyte and embryo pilRNAs exhibited many of the canonical characteristics of piRNAs including a 1U bias, the presence of a ‘ping-pong’ signature, genomic clustering, and transposable element targeting. Some of the major transposons targeted by oocyte and zygote pilRNA were from the LINE RTE and ERV1 classes. We also identified pools of pilRNA potentially derived from, or targeted at, specific mRNA sequences. We compared the frequency of these gene-associated pilRNAs to the fold change in the expression of respective mRNAs from two previously reported transcriptome datasets. We observed significant negative correlations between the number of pilRNAs targeting mRNAs, and their fold change in expression between the 4–8 cell and 8–16 cell stages. Together, these results represent one of the first characterizations of the PIWI/piRNA pathway in the translational bovine model, and in the novel context of embryogenesis.


Botany ◽  
2018 ◽  
Vol 96 (4) ◽  
pp. 235-247 ◽  
Author(s):  
Gaolathe Rantong ◽  
Arunika H.L.A.N. Gunawardena

Perforation formation in Aponogeton madagascariensis (Mirb.) H.Bruggen (lace plant) is an excellent model for studying developmentally regulated programmed cell death (PCD). In this study, we isolated and identified two lace plant vacuolar processing enzymes (VPEs) and investigated their involvement in PCD and throughout leaf development. Lace plant VPE transcript levels were determined during seven different stages of leaf development. PCD and non-PCD cells from “window” stage leaves (in which perforations are forming) were separated through laser-capture microscopy and their transcript levels were also determined. VPE activity was also studied between the cell types, through a VPE activity-based probe JOPD1. Additionally, VPE transcript levels were studied in plants treated with an ethylene biosynthesis inhibitor, aminoethoxyvinylglycine (AVG). The two isolated VPEs, AmVPE1 and AmVPE2, are vegetative type VPEs. AmVPE1 had higher transcript levels during a pre-perforation developmental stage, immediately prior to visible signs of PCD. AmVPE2 transcript levels were higher later during window and late window stages. Both VPEs had higher transcript and activity levels in PCD compared with the non-PCD cells. AVG treatment inhibited PCD and associated increases in VPE transcript levels. Our results suggested that VPEs are involved in the execution of the ethylene-related PCD in the lace plant.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nathan M. Rowarth ◽  
Bruce A. Curtis ◽  
Anthony L. Einfeldt ◽  
John M. Archibald ◽  
Christian R. Lacroix ◽  
...  

Abstract Background The lace plant (Aponogeton madagascariensis) is an aquatic monocot that develops leaves with uniquely formed perforations through the use of a developmentally regulated process called programmed cell death (PCD). The process of perforation formation in lace plant leaves is subdivided into several developmental stages: pre-perforation, window, perforation formation, perforation expansion and mature. The first three emerging “imperforate leaves” do not form perforations, while all subsequent leaves form perforations via developmentally regulated PCD. PCD is active in cells called “PCD cells” that do not retain the antioxidant anthocyanin in spaces called areoles framed by the leaf veins of window stage leaves. Cells near the veins called “NPCD cells” retain a red pigmentation from anthocyanin and do not undergo PCD. While the cellular changes that occur during PCD are well studied, the gene expression patterns underlying these changes and driving PCD during leaf morphogenesis are mostly unknown. We sought to characterize differentially expressed genes (DEGs) that mediate lace plant leaf remodelling and PCD. This was achieved performing gene expression analysis using transcriptomics and comparing DEGs among different stages of leaf development, and between NPCD and PCD cells isolated by laser capture microdissection. Results Transcriptomes were sequenced from imperforate, pre-perforation, window, and mature leaf stages, as well as PCD and NPCD cells isolated from window stage leaves. Differential expression analysis of the data revealed distinct gene expression profiles: pre-perforation and window stage leaves were characterized by higher expression of genes involved in anthocyanin biosynthesis, plant proteases, expansins, and autophagy-related genes. Mature and imperforate leaves upregulated genes associated with chlorophyll development, photosynthesis, and negative regulators of PCD. PCD cells were found to have a higher expression of genes involved with ethylene biosynthesis, brassinosteroid biosynthesis, and hydrolase activity whereas NPCD cells possessed higher expression of auxin transport, auxin signalling, aspartyl proteases, cysteine protease, Bag5, and anthocyanin biosynthesis enzymes. Conclusions RNA sequencing was used to generate a de novo transcriptome for A. madagascariensis leaves and revealed numerous DEGs potentially involved in PCD and leaf remodelling. The data generated from this investigation will be useful for future experiments on lace plant leaf development and PCD in planta.


2018 ◽  
Author(s):  
Yi-Chun Huang ◽  
Henry Moreno ◽  
Sarayu Row ◽  
Dongyu Jia ◽  
Wu-Min Deng

AbstractOne of the most extensively used techniques in Drosophila is the Gal4/UAS binary system, which allows tissue-specific misexpression or knockdown of specific genes of interest. The original UAS vector, UASt, can only be activated for transgene expression in somatic tissues and not in the germline cells. Rørth (1998) generated UASp, a modified UAS vector that is responsive to Gal4 in both somatic and germline tissues, by replacing both the hsp70 promoter and the SV40 3’UTR with the P transposase promoter and the K10 3’UTR respectively. At present, the mechanisms by which UASt is silenced in germline cells are not fully understood. Here, we report that the piRNA pathway is involved in suppressing UASt expression in ovarian germline cells. Individually knocking down or mutating components of the piRNA biogenesis pathway (e.g., Piwi, AGO3, Aub, Spn-E, and Vasa) resulted in the expression of the UASt-reporter (GFP or RFP) in the germline. An RNA-seq analysis of small RNAs revealed that the hsp70 promoter of UASt is targeted by piRNAs, and in the aub mutant ovary, the amount of piRNAs targeting the hsp70 promoter is reduced by around 40 folds. In contrast, the SV40 3’UTR of the UASt, which happens to be targeted by the Nonsense-mediated RNA decay (NMD) pathway, is not responsible for germline UASt suppression, as UASt-reporters with NMD-insensitive 3’UTRs fail to show germline expression. Taken together, our studies reveal a crucial role of the piRNA pathway, potentially via the suppression of the hsp70 promoter, in germline UASt silencing in Drosophila ovaries.


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