Tissue-specific silencing of integrated transgenes achieved through endogenous RNA interference in Caenorhabditis elegans

ABSTRACT

Transgene silencing is a common phenomenon observed in Caenorhabditis elegans, particularly in the germline, but the precise mechanisms underlying this process remain elusive. Through an analysis of the transcription factors profile of C. elegans, we discovered that the expression of several transgenic reporter lines exhibited tissue-specific silencing, specifically in the intestine of C. elegans. Notably, this silencing could be reversed in mutants defective in endogenous RNA interference (RNAi). Further investigation using knock-in strains revealed that these intestine-silent genes were indeed expressed in vivo, indicating that the organism itself regulates the intestine-specific silencing. This tissue-specific silencing appears to be mediated through the endo-RNAi pathway, with the main factors of this pathway, mut-2 and mut-16, are significantly enriched in the intestine. Additionally, histone modification factors, such as met-2, are involved in this silencing mechanism. Given the crucial role of the intestine in reproduction alongside the germline, the transgene silencing observed in the intestine reflects the self-protective mechanisms employed by the organisms. In summary, our study proposed that compared to other tissues, the transgenic silencing of intestine is specifically regulated by the endo-RNAi pathway.

KEYWORDS:

• C. elegans
• transgene silencing
• endo-RNAi
• tissue-specific

Acknowledgments

We thank Prof. Xiao Liu for discussion, Dr. Shouhong Guang for suggestions, Dr. Yang Chen and Qi Yan from Guang lab for providing some of the strains important for genetic analysis, members of Liu lab for discussions, Dr. Qiangfeng Cliff Zhang for comments on this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

D. Z. conceived and designed the study, secured funding, and reviewed the manuscript; S. C. and W. L. designed and performed laboratory experiments; L. X. worked on gene set enrichment analysis; Z. T. performed transgenic worms generation. All authors have read and agreed to the published version of the manuscript.

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article and its supplementary materials.

Supplemental data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15476286.2024.2332856

Additional information

Funding

This research was funded by National Natural Science Foundation of China, grant number 32200486.