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Arabidopsis FRS 4/ CPD 25 and FHY 3/ CPD 45 work cooperatively to promote the expression of the chloroplast division gene ARC 5 and chloroplast division
Author(s) -
Gao Yuefang,
Liu Han,
An Chuanjing,
Shi Yuhong,
Liu Xia,
Yuan Wanqiong,
Zhang Bing,
Yang Jin,
Yu Caixia,
Gao Hongbo
Publication year - 2013
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12240
Subject(s) - arc (geometry) , mutant , microbiology and biotechnology , gene , chloroplast , biology , chemistry , genetics , geometry , mathematics
Summary ARC 5 is a dynamin‐related GTP ase essential for the division of chloroplasts in plants. The arc5 mutant frequently exhibits enlarged, dumbbell‐shaped chloroplasts, indicating a role for ARC 5 in the constriction of the chloroplast division site. In a screen for chloroplast division mutants with a phenotype similar to arc5 , two mutants, cpd25 and cpd45 , were obtained. CPD 45 was identified as being the same gene as FHY 3 , a key regulator of far‐red light signaling recently shown to be involved in the regulation of ARC 5 . CPD 25 was previously named FRS 4 and is homologous to FHY 3 . We found that CPD 25 is also required for the expression of ARC 5 , suggesting that its function is not redundant to that of FHY 3 . Moreover, cpd25 does not have the far‐red light‐sensing defect present in fhy3 and far1 . Both FRS 4/ CPD 25 and FHY 3/ CPD 45 could bind to the FBS ‐like ‘ ACGCGC ’ motifs in the promoter region of ARC 5 , and the binding efficiency of FRS 4/ CPD 25 was much higher than that of FHY 3/ CPD 45. Unlike FHY 3/ CPD 45, FRS 4/ CPD 25 has no ARC 5 activation activity. Our data suggest that FRS 4/ CPD 25 and FHY 3/ CPD 45 function as a heterodimer that cooperatively activates ARC 5 , that FRS 4/ CPD 25 plays the major role in promoter binding, and that FHY 3/ CPD 45 is largely responsible for the gene activation. This study not only provides insight into the mechanisms underlying the regulation of chloroplast division in higher plants, but also suggests a model that shows how members of a transcription factor family can evolve to have different DNA ‐binding and gene activation features.