biostudies-literatureUnknown16(1)Pan ZJHelper-component proteinase (HC-Pro), encoded by potyviruses, function as viral suppressors of RNA silencing (VSRs). Despite their conserved role, HC-Pros share approximately 40% similarity, implying potential differences in VSR efficiency, particularly in their ability to inhibit HEN1 methyltransferase activity. This study investigated the inhibitory potential of HC-Pros from different potyviruses in transgenic plants. P1/HC-Pro from turnip mosaic virus (P1/HC-Pro^Tu) exhibited the most potent inhibition of HEN1, followed by P1/HC-Pro from zucchini yellow mosaic virus (P1/HC-Pro^Zy), while P1/HC-Pro from tobacco etch virus (P1/HC-Pro^Te) showed the weakest inhibitory effect. These differential effectual effects corresponded to variations in unmethylated microNature communications2503https://www.ebi.ac.uk/biostudies/studies/S-EPMC11906750biostudies-literatureHC-Pro inhibits HEN1 methyltransferase activity, leading to autophagic degradation of AGO1.PMC11906750Cheng CHPham THFang RYBowman JLShen TLLin SSJane WNYang JTLin PCHung YLHu SFWu HYShang QWWei WLShen BNChang HHChung CTLin CSTran PAHong SFWu FHWang CCPan ZJfalseHC-Pro inhibits HEN1 methyltransferase activity, leading to autophagic degradation of AGO1.Helper-component proteinase (HC-Pro), encoded by potyviruses, function as viral suppressors of RNA silencing (VSRs). Despite their conserved role, HC-Pros share approximately 40% similarity, implying potential differences in VSR efficiency, particularly in their ability to inhibit HEN1 methyltransferase activity. This study investigated the inhibitory potential of HC-Pros from different potyviruses in transgenic plants. P1/HC-Pro from turnip mosaic virus (P1/HC-Pro^Tu) exhibited the most potent inhibition of HEN1, followed by P1/HC-Pro from zucchini yellow mosaic virus (P1/HC-Pro^Zy), while P1/HC-Pro from tobacco etch virus (P1/HC-Pro^Te) showed the weakest inhibitory effect. These differential effectual effects corresponded to variations in unmethylated micro2025-01-01T00:00:00Z2025 Mar2026-03-18T13:20:29.793Z2025-04-05T22:07:42.006ZS-EPMC119067504008239610.1038/s41467-025-56320-z