UMMS Affiliation

Program in Bioinformatics and Integrative Biology; Program in Molecular Medicine; Department of Neurobiology

Publication Date


Document Type



Biochemistry, Biophysics, and Structural Biology | Bioinformatics | Cell Biology | Computational Biology | Developmental Biology | Genetics and Genomics | Systems Biology


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, approximately 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.


Manduca sexta, RNA interference, development, ping-pong amplification, small RNAs, transposon

Rights and Permissions

Copyright © 2021 Tsuji, Thomson, Brown, Ghosh, Theurkauf, Weng and Schwartz. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

DOI of Published Version



Tsuji J, Thomson T, Brown C, Ghosh S, Theurkauf WE, Weng Z, Schwartz LM. Somatic piRNAs and Transposons are Differentially Expressed Coincident with Skeletal Muscle Atrophy and Programmed Cell Death. Front Genet. 2021 Dec 22;12:775369. doi: 10.3389/fgene.2021.775369. PMID: 35003216; PMCID: PMC8730325. Link to article on publisher's site

Journal/Book/Conference Title

Frontiers in genetics

Related Resources

Link to Article in PubMed

PubMed ID


Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.