Role of Extrachromosomal Circular DNA in Sex Reversal of Monopterus albus
- 1State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
- 2Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China
Abstract
Extrachromosomal circular DNA (eccDNA) serves as a vital regulator of gene expression and phenotypic plasticity. The Monopterus albus is a protogynous hermaphroditic fish, and the functional role of eccDNA during its female-to-male sex reversal remains poorly understood. We conducted Circle-seq analysis on gonadal tissues of super-female and male individuals and integrated our findings with previously published gonadal RNA-seq data. A total of 62,574 and 34,562 eccDNAs were, on average, identified in the two groups, and 7881 down-regulated and 2738 up-regulated differentially abundant eccDNAs were screened in male gonads. Three candidate eccDNAs, eccDNADmrt1a, eccDNASox9a1 and eccDNAZNF239, were selected for subsequent analysis. Quantitative real-time PCR was applied to detect the overall transcriptional levels of their corresponding host genes, covering transcripts derived from both genomic DNA and eccDNA. Spatiotemporal expression profiling and letrozole induction experiments revealed male-biased expression of Dmrt1a and Sox9a1, while ZNF239 was predominantly expressed in female gonads. Complete sex reversal was observed in female M. albus after 90-day letrozole treatment, accompanied by elevated Dmrt1a/Sox9a1 and reduced ZNF239 transcription. Fluorescence in situ hybridization localized these transcripts in gonadal germ cells and somatic cells across developmental stages. This study verifies the production of eccDNA during gonadal development. The results indicate that Dmrt1a and Sox9a1 may facilitate sex reversal and suggest that ZNF239 is likely involved in ovarian development. This work provides novel clues for deciphering the molecular mechanism underlying sex reversal from the eccDNA perspective.
Related
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BibTeX
@article{fang2026role,
title = {{Role of Extrachromosomal Circular DNA in Sex Reversal of Monopterus albus}},
author = {Junchao Fang and Guanglve Li and Wenyin Luo and Haifeng Tian and Qiaomu Hu},
journal = {Biomolecules},
year = {2026},
month = oct,
doi = {10.3390/biom16101480},
url = {https://www.mdpi.com/2218-273X/16/10/1480},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Role of Extrachromosomal Circular DNA in Sex Reversal of Monopterus albus
AU - Junchao Fang
AU - Guanglve Li
AU - Wenyin Luo
AU - Haifeng Tian
AU - Qiaomu Hu
PY - 2026
DA - 2026/10/01
JO - Biomolecules
DO - 10.3390/biom16101480
UR - https://www.mdpi.com/2218-273X/16/10/1480
AB - Extrachromosomal circular DNA (eccDNA) serves as a vital regulator of gene expression and phenotypic plasticity. The Monopterus albus is a protogynous hermaphroditic fish, and the functional role of eccDNA during its female-to-male sex reversal remains poorly understood. We conducted Circle-seq analysis on gonadal tissues of super-female and male individuals and integrated our findings with previously published gonadal RNA-seq data. A total of 62,574 and 34,562 eccDNAs were, on average, identified in the two groups, and 7881 down-regulated and 2738 up-regulated differentially abundant eccDNAs were screened in male gonads. Three candidate eccDNAs, eccDNADmrt1a, eccDNASox9a1 and eccDNAZNF239, were selected for subsequent analysis. Quantitative real-time PCR was applied to detect the overall transcriptional levels of their corresponding host genes, covering transcripts derived from both genomic DNA and eccDNA. Spatiotemporal expression profiling and letrozole induction experiments revealed male-biased expression of Dmrt1a and Sox9a1, while ZNF239 was predominantly expressed in female gonads. Complete sex reversal was observed in female M. albus after 90-day letrozole treatment, accompanied by elevated Dmrt1a/Sox9a1 and reduced ZNF239 transcription. Fluorescence in situ hybridization localized these transcripts in gonadal germ cells and somatic cells across developmental stages. This study verifies the production of eccDNA during gonadal development. The results indicate that Dmrt1a and Sox9a1 may facilitate sex reversal and suggest that ZNF239 is likely involved in ovarian development. This work provides novel clues for deciphering the molecular mechanism underlying sex reversal from the eccDNA perspective.
SN - 2218-273X
ER -