]*>","")" /> Allelic Analyses of the <i>Arabidopsis YUC1</i> Locus Reveal Residues and Domains Essential for the Functions of YUC Family of Flavin Monooxygenases

J Integr Plant Biol ›› 2011, Vol. 53 ›› Issue (1): 54-62.DOI: 10.1111/j.1744-7909.2010.01007.x

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Allelic Analyses of the Arabidopsis YUC1 Locus Reveal Residues and Domains Essential for the Functions of YUC Family of Flavin Monooxygenases

Xianhui Hou1,2†, Sainan Liu1,2†, Florencia Pierri2, Xinhua Dai2, Li-Jia Qu1 and Yunde Zhao2*   

  • 收稿日期:2010-09-09 接受日期:2010-11-04 出版日期:2010-11-10 发布日期:2010-11-10

Allelic Analyses of the Arabidopsis YUC1 Locus Reveal Residues and Domains Essential for the Functions of YUC Family of Flavin Monooxygenases

Xianhui Hou1,2†, Sainan Liu1,2†, Florencia Pierri2, Xinhua Dai2, Li-Jia Qu1 and Yunde Zhao2*   

  1. 1National Laboratory for Protein Engineering and Plant Genetic Engineering, Peking-Yale Joint Research Center for Plant Molecular Genetics and AgroBiotechnology, College of Life Sciences, Peking University, Beijing 100871, China
    2Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, California 92093-0116, USA
  • Received:2010-09-09 Accepted:2010-11-04 Online:2010-11-10 Published:2010-11-10
  • About author:*Corresponding author Tel +1 858 822 2670 Fax: +1 858 534 7108 E-mail:yundezhao@ucsd.edu
    †Contributed equally to this paper.

Abstract:

Flavin monooxygenases (FMOs) play critical roles in plant growth and development by synthesizing auxin and other signaling molecules. However, the structure and function relationship within plant FMOs is not understood. Here we defined the important residues and domains of the Arabidopsis YUC1 FMO, a key enzyme in auxin biosynthesis. We previously showed that simultaneous inactivation of YUC1 and its homologue YUC4 caused severe defects in vascular and floral development. We mutagenized the yuc4 mutant and screened for mutants with phenotypes similar to those of yuc1 yuc4 double mutants. Among the isolated mutants, five of them contained mutations in the YUC1 gene. Interestingly, the mutations identified in the new yuc1 alleles were concentrated in the two GXGXXG motifs that are highly conserved among the plant FMOs. One such motif presumably binds to flavin adenine dinucleotide (FAD) cofactor and the other binds to nicotinamide adenine dinucleotide phosphate (NADPH). We also identified the Ser139 to Phe conversion in yuc1, a mutation that is located between the two nucleotide-binding sites. By analyzing a series of yuc1 mutants, we identified key residues and motifs essential for the functions of YUC1 FMO.

Hou X, Liu S, Pierri F, Dai X, Qu LJ, Zhao Y (2011) Allelic analyses of the Arabidopsis YUC1 locus reveal residues and domains essential for the functions of YUC family of flavin monooxygenases. J. Integr. Plant Biol. 53(1), 54–62.

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