T-Box

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Xing Wang Deng - One of the best experts on this subject based on the ideXlab platform.

  • b box containing proteins bbx30 and bbx31 acting downstream of hy5 negatively regulate photomorphogenesis in arabidopsis
    2019
    Co-Authors: Dongqing Xu, Yan Jiang, Xing Wang Deng, Yueqin Heng, Mingquan Ding, Hua Zhou, Xianhai Zhao
    Abstract:

    Light-mediated seedling development is coordinately controlled by a variety of key regulators. Here, we identified two B-box (BBX)-containing proteins, BBX30 and BBX31, as repressors of photomorphogenesis. ELONGATED HYPOCOTYL5, a central regulator of light signaling, directly binds to the G-box cis-element present in the promoters of BBX30 and BBX31 and negatively controls their transcription levels in the light. Seedlings with mutations in BBX30 or BBX31 are hypersensitive to light, whereas the overexpression of BBX30 or BBX31 leads to hypo-photomorphogenic growth in the light. Furthermore, transgenic and phenotypic analysis revealed that the B-box domain of BBX30 or BBX31 is essential for their respective functioning in the regulation of photomorphogenic development in plants. In conclusion, BBX30 and BBX31 act as key negative regulators of light signaling, and their transcription is repressed by ELONGATED HYPOCOTYL5 through directly associating with their promoters.

  • the b box domain protein bbx21 promotes photomorphogenesis
    2017
    Co-Authors: Dongqing Xu, Yan Jiang, Jian Li, Magnus Holm, Xing Wang Deng
    Abstract:

    B-box-containing (BBX) proteins play critical roles in a variety of cellular and developmental processes in plants. BBX21 (also known as SALT TOLERANCE HOMOLOG2), which contains two B-box domains in tandem at the N terminus, has been previously demonstrated as a key component involved in the COP1-HY5 signaling hub. However, the exact molecular and physiological roles of B-box domains in BBX21 are largely unclear. Here, we found that structurally disruption of the second B-box domain, but not the first one, in BBX21 completely abolishes its biological and physiological activity in conferring hyperphotomorphogenetic phenotype in Arabidopsis (Arabidopsis thaliana). Intact B-box domains in BBX21 are not required for interaction with COP1 and its degradation by COP1 via the 26S proteasome system. However, disruption of the second B-box of BBX21 nearly impairs its ability for binding of T/G-box within the HY5 promoter both in vitro and in vivo, as well as controlling HY5 and HY5-regulated gene expression in Arabidopsis seedlings. Taken together, this study provides a mechanistic framework in which BBX21 directly binds to the T/G-box present in the HY5 promoter possibly through its second B-box domain, which in turn controls HY5 and HY5-regulated gene expression to promote photomorphogenesis.

  • bbx21 an arabidopsis b box protein directly activates hy5 and is targeted by cop1 for 26s proteasome mediated degradation
    2016
    Co-Authors: Yan Jiang, Magnus Holm, Fang Lin, Xing Wang Deng
    Abstract:

    BBX21 (also known as SALT TOLERANCE HOMOLOG 2), a B-box (BBX)-containing protein, has been previously identified as a positive regulator of light signaling; however, the precise role of BBX21 in regulating seedling photomorphogenesis remains largely unclear. In this study, we report that CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) interacts with BBX21 in vivo and is able to ubiquitinate BBX21 in vitro. Thus, BBX21 is targeted for 26S proteasome-mediated degradation in dark-grown Arabidopsis seedlings in a COP1-dependent manner. Moreover, we show that BBX21 binds to the T/G-box in the ELONGATED HYPOCOTYL 5 (HY5) promoter and directly activates HY5 expression in the light. Transgenic seedlings overexpressing BBX21 exhibit dramatically shortened hypocotyls in the light, and this phenotype is dependent on a functional HY5. Taken together, our data suggest a molecular base underlying BBX21-mediated seedling photomorphogenesis, indicating that BBX21 is a pivotal component involved in the COP1-HY5 regulatory hub.

Christoph W Muller - One of the best experts on this subject based on the ideXlab platform.

  • structure of the dna bound t box domain of human tbx3 a transcription factor responsible for ulnar mammary syndrome
    2002
    Co-Authors: Miquel Coll, J G Seidman, Christoph W Muller
    Abstract:

    T-Box genes encode transcription factors involved in morphogenesis and organogenesis of vertebrates and invertebrates. Mutations in human T-Box genes TBX3, TBX5, and TBX1 cause severe genetic disorders known as Ulnar-Mammary syndrome (UMS), Holt-Oram syndrome (HOS), and DiGeorge syndrome, respectively. The crystal structure of the T-Box domain of the first human T-Box transcription factor, TBX3, in complex with DNA at 1.7 A resolution explains structural consequences of T-Box domain point mutations observed in UMS and HOS patients. Comparison with the structure of the T-Box domain from Xenopus laevis (Xbra) bound to DNA shows differences in several secondary structure elements and in the quaternary structure of the two complexes. TBX3 independently recognizes the two binding sites present in the palindromic DNA duplex, whereas in Xbra, binding to the palindrome is stabilized through interactions between the two monomers. The different quaternary structures suggest different DNA binding modes for T-Box transcription factors.

Yan Jiang - One of the best experts on this subject based on the ideXlab platform.

  • b box containing proteins bbx30 and bbx31 acting downstream of hy5 negatively regulate photomorphogenesis in arabidopsis
    2019
    Co-Authors: Dongqing Xu, Yan Jiang, Xing Wang Deng, Yueqin Heng, Mingquan Ding, Hua Zhou, Xianhai Zhao
    Abstract:

    Light-mediated seedling development is coordinately controlled by a variety of key regulators. Here, we identified two B-box (BBX)-containing proteins, BBX30 and BBX31, as repressors of photomorphogenesis. ELONGATED HYPOCOTYL5, a central regulator of light signaling, directly binds to the G-box cis-element present in the promoters of BBX30 and BBX31 and negatively controls their transcription levels in the light. Seedlings with mutations in BBX30 or BBX31 are hypersensitive to light, whereas the overexpression of BBX30 or BBX31 leads to hypo-photomorphogenic growth in the light. Furthermore, transgenic and phenotypic analysis revealed that the B-box domain of BBX30 or BBX31 is essential for their respective functioning in the regulation of photomorphogenic development in plants. In conclusion, BBX30 and BBX31 act as key negative regulators of light signaling, and their transcription is repressed by ELONGATED HYPOCOTYL5 through directly associating with their promoters.

  • the b box domain protein bbx21 promotes photomorphogenesis
    2017
    Co-Authors: Dongqing Xu, Yan Jiang, Jian Li, Magnus Holm, Xing Wang Deng
    Abstract:

    B-box-containing (BBX) proteins play critical roles in a variety of cellular and developmental processes in plants. BBX21 (also known as SALT TOLERANCE HOMOLOG2), which contains two B-box domains in tandem at the N terminus, has been previously demonstrated as a key component involved in the COP1-HY5 signaling hub. However, the exact molecular and physiological roles of B-box domains in BBX21 are largely unclear. Here, we found that structurally disruption of the second B-box domain, but not the first one, in BBX21 completely abolishes its biological and physiological activity in conferring hyperphotomorphogenetic phenotype in Arabidopsis (Arabidopsis thaliana). Intact B-box domains in BBX21 are not required for interaction with COP1 and its degradation by COP1 via the 26S proteasome system. However, disruption of the second B-box of BBX21 nearly impairs its ability for binding of T/G-box within the HY5 promoter both in vitro and in vivo, as well as controlling HY5 and HY5-regulated gene expression in Arabidopsis seedlings. Taken together, this study provides a mechanistic framework in which BBX21 directly binds to the T/G-box present in the HY5 promoter possibly through its second B-box domain, which in turn controls HY5 and HY5-regulated gene expression to promote photomorphogenesis.

  • bbx21 an arabidopsis b box protein directly activates hy5 and is targeted by cop1 for 26s proteasome mediated degradation
    2016
    Co-Authors: Yan Jiang, Magnus Holm, Fang Lin, Xing Wang Deng
    Abstract:

    BBX21 (also known as SALT TOLERANCE HOMOLOG 2), a B-box (BBX)-containing protein, has been previously identified as a positive regulator of light signaling; however, the precise role of BBX21 in regulating seedling photomorphogenesis remains largely unclear. In this study, we report that CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) interacts with BBX21 in vivo and is able to ubiquitinate BBX21 in vitro. Thus, BBX21 is targeted for 26S proteasome-mediated degradation in dark-grown Arabidopsis seedlings in a COP1-dependent manner. Moreover, we show that BBX21 binds to the T/G-box in the ELONGATED HYPOCOTYL 5 (HY5) promoter and directly activates HY5 expression in the light. Transgenic seedlings overexpressing BBX21 exhibit dramatically shortened hypocotyls in the light, and this phenotype is dependent on a functional HY5. Taken together, our data suggest a molecular base underlying BBX21-mediated seedling photomorphogenesis, indicating that BBX21 is a pivotal component involved in the COP1-HY5 regulatory hub.

Xiangqi Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Genome-wide analysis of the MADS-box gene family in Brachypodium distachyon.
    2014
    Co-Authors: Bo Wei, Rongzhi Zhang, Juan-juan Guo, Danmei Liu, Fan Renchun, Long Mao, Xiangqi Zhang
    Abstract:

    MADS-box genes are important transcription factors for plant development, especially floral organogenesis. Brachypodium distachyon is a model for biofuel plants and temperate grasses such as wheat and barley, but a comprehensive analysis of MADS-box family proteins in Brachypodium is still missing. We report here a genome-wide analysis of the MADS-box gene family in Brachypodium distachyon. We identified 57 MADS-box genes and classified them into 32 MIKCc-type, 7 MIKC*-type, 9 Mα, 7 Mβ and 2 Mγ MADS-box genes according to their phylogenetic relationships to the Arabidopsis and rice MADS-box genes. Detailed gene structure and motif distribution were then studied. Investigation of their chromosomal localizations revealed that Brachypodium MADS-box genes distributed evenly across five chromosomes. In addition, five pairs of type II MADS-box genes were found on synteny blocks derived from whole genome duplication blocks. We then performed a systematic expression analysis of Brachypodium MADS-box genes in various tissues, particular floral organs. Further detection under salt, drought, and low-temperature conditions showed that some MADS-box genes may also be involved in abiotic stress responses, including type I genes. Comparative studies of MADS-box genes among Brachypodium, rice and Arabidopsis showed that Brachypodium had fewer gene duplication events. Taken together, this work provides useful data for further functional studies of MADS-box genes in Brachypodium distachyon.

Miquel Coll - One of the best experts on this subject based on the ideXlab platform.

  • structure of the dna bound t box domain of human tbx3 a transcription factor responsible for ulnar mammary syndrome
    2002
    Co-Authors: Miquel Coll, J G Seidman, Christoph W Muller
    Abstract:

    T-Box genes encode transcription factors involved in morphogenesis and organogenesis of vertebrates and invertebrates. Mutations in human T-Box genes TBX3, TBX5, and TBX1 cause severe genetic disorders known as Ulnar-Mammary syndrome (UMS), Holt-Oram syndrome (HOS), and DiGeorge syndrome, respectively. The crystal structure of the T-Box domain of the first human T-Box transcription factor, TBX3, in complex with DNA at 1.7 A resolution explains structural consequences of T-Box domain point mutations observed in UMS and HOS patients. Comparison with the structure of the T-Box domain from Xenopus laevis (Xbra) bound to DNA shows differences in several secondary structure elements and in the quaternary structure of the two complexes. TBX3 independently recognizes the two binding sites present in the palindromic DNA duplex, whereas in Xbra, binding to the palindrome is stabilized through interactions between the two monomers. The different quaternary structures suggest different DNA binding modes for T-Box transcription factors.