Author:
Zhang Changqing,Hung Yu-Hung,Zhang Xiang-Qian,Zhang Dapeng,Xiao Wenyan,Iyer Lakshminarayan M.,Aravind L.,Huh Jin Hoe,Hsieh Tzung-Fu
Abstract
AbstractDNA methylation plays critical roles in maintaining genome stability, genomic imprinting, transposon silencing, and development. In Arabidopsis genomic imprinting is established in the central cell by DEMETER (DME)-mediated active DNA demethylation, and is essential for seed viability. DME is a large polypeptide with multiple poorly characterized conserved domains. Here we show that the C-terminal enzymatic core of DME is sufficient to complement dme associated developmental defects. When targeted by a native DME promoter, nuclear-localized DME C-terminal region rescues dme seed abortion and pollen germination defects, and ameliorates CG hypermethylation phenotype in dme-2 endosperm. Furthermore, targeted expression of the DME N-terminal region in wild-type central cell induces dme-like seed abortion phenotype. Our results support a bipartite organization for DME protein, and suggest that the N-terminal region might have regulatory function such as assisting in DNA binding and enhancing the processivity of active DNA demethylation in heterochromatin targets.
Publisher
Cold Spring Harbor Laboratory