Botany Plant Molecular Genetics BPG001


Holliday junctions, four-stranded DNA structures formed during homologous recombination, are disentangled by resolvases that have been found in prokaryotes and eukaryotes but not in plant organelles. Here, we identify monokaryotic chloroplast 1 (MOC1) as a Holliday junction resolvase in chloroplasts by analyzing a green alga (Chlamydomonas reinhardtii) mutant defective in chloroplast nucleoid (DNA-protein complex) segregation (A). MOC1 is structurally similar to a bacterial Holliday junction resolvase, resistance to ultraviolet (Ruv) C, and genetically conserved among green plants. Reduced or no expression of MOC1 in Arabidopsis thaliana leads to growth defects and aberrant chloroplast nucleoid segregation. In vitro biochemical analysis and high-speed atomic force microscopic analysis revealed that A. thaliana MOC 1 (AtMOC1) binds and cleaves the core of Holliday junctions symmetrically (B). MOC1 may mediate chloroplast nucleoid segregation in green plants by resolving Holliday junctions.



Prefecture Kyoto Use of Microscope Use
Region Yoshida Campus, Kyoto University Use of Automatic Shooting Devices Don't Use
Shooting Date --- Use of Fluorescent Probe Use
Shooting Time --- Use of Infrared Don't Use
Photographer Yusuke KOBAYASHI Shooting Interval (Sec.) 使用しない
Copyright Holder Yusuke KOBAYASHI Shooting Speed ---

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