Molecular Characteristics, Circularization Mechanism, and Potential Functions of circRNA-0172.

Abstract

<h4>Background/objectives</h4>Avian leukosis virus subgroup J (ALV-J) harms poultry via tumors and immunosuppression; MDM2-derived circRNA-0172's role in ALV-J infection is unknown. This study explores its molecular characteristics, circularization mechanism and functions for ALV-J control.<h4>Methods</h4>CEF/DF-1/HD11 cells were cultured; RNA/DNA was extracted. circRNA-0172 was validated via PCR, sequencing and RNase R; subcellular localization and circularization were analyzed with fractionation and vectors. miRanda/TargetScan/GO/KEGG, CCK-8 and qRT-PCR assessed targets, pathways and functions.<h4>Results</h4>circRNA-0172 (1180 bp, MDM2 exons 3-11) is cytoplasm localized, RNase R resistant, and circularized via flanking ERVL-MaLR repeats. Highly expressed in immune tissues/HD11 cells, it is downregulated by ALV-J. Its overexpression inhibits DF-1 proliferation, downregulates Bcl2 and upregulates CCND1.<h4>Conclusions</h4>This is the first confirmation of circRNA-0172's stability and repeat-dependent circularization; it regulates cell proliferation/apoptosis, providing potential targets for ALV-J-associated avian leukemia.