Modular in vivo assembly of Arabidopsis FCA oligomers into condensates competent for RNA 3’ processing

TY - JOUR

T1 - Modular in vivo assembly of Arabidopsis FCA oligomers into condensates competent for RNA 3’ processing

AU - Jang, Geng-Jen

AU - Payne-Dwyer, Alex

AU - Maple, Robert

AU - Wu, Zhe

AU - Liu, Fuquan

AU - Lopez, Sergio

AU - Wang, Yanning

AU - Fang, Xiaofeng

AU - Leake, Mark Christian

AU - Dean, Caroline

N1 - © The Author(s)

PY - 2025/2/24

Y1 - 2025/2/24

N2 - Our understanding of the functional requirements underpinning biomolecular condensation in vivo is still relatively poor. The Arabidopsis RNA binding protein FCA is found in liquid-like nuclear condensates that function in transcription termination, promoting proximal polyadenylation at many targets in the Arabidopsis genome. To further understand the properties of these condensates in vivo we used single particle tracking experiments on FCA reporters stably expressed at endogenous levels in plant nuclei. These revealed FCA forms a core oligomer of ~4 molecules that multimerizes into higher-order particles. This assembles into macromolecular condensates through the function of the coiled-coil protein FLL2, which is genetically required for FCA function. FLL2 predominately co25 localizes with FCA in larger sized condensates. A missense mutation in the FCA RRM domain, also genetically required for FCA function, reduced both average FCA particle and condensate size but did not perturb the core oligomer. Our work points to a modular structure for FCA condensates involving multimerization of core oligomers that assemble into functional macromolecular condensates via associated RNA and FLL2 interactions.

AB - Our understanding of the functional requirements underpinning biomolecular condensation in vivo is still relatively poor. The Arabidopsis RNA binding protein FCA is found in liquid-like nuclear condensates that function in transcription termination, promoting proximal polyadenylation at many targets in the Arabidopsis genome. To further understand the properties of these condensates in vivo we used single particle tracking experiments on FCA reporters stably expressed at endogenous levels in plant nuclei. These revealed FCA forms a core oligomer of ~4 molecules that multimerizes into higher-order particles. This assembles into macromolecular condensates through the function of the coiled-coil protein FLL2, which is genetically required for FCA function. FLL2 predominately co25 localizes with FCA in larger sized condensates. A missense mutation in the FCA RRM domain, also genetically required for FCA function, reduced both average FCA particle and condensate size but did not perturb the core oligomer. Our work points to a modular structure for FCA condensates involving multimerization of core oligomers that assemble into functional macromolecular condensates via associated RNA and FLL2 interactions.

U2 - 10.1038/s44318-025-00394-4

DO - 10.1038/s44318-025-00394-4

M3 - Article

SN - 0261-4189

VL - 44

SP - 2056

EP - 2074

JO - EMBO Journal

JF - EMBO Journal

IS - 7

ER -