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Molecular Cloning, Purification and Characterization of Mce1R of Mycobacterium tuberculosis. Mol Biotechnol 2021; 63:200-220. [PMID: 33423211 DOI: 10.1007/s12033-020-00293-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/18/2020] [Indexed: 10/22/2022]
Abstract
The mce1 operon of Mycobacterium tuberculosis, important for lipid metabolism/transport, host cell invasion, modulation of host immune response and pathogenicity, is under the transcriptional control of Mce1R. Hence characterizing Mce1R is an important step for novel anti-tuberculosis drug discovery. The present study reports functional and in silico characterization of Mce1R. In this work, we have computationally modeled the structure of Mce1R and have validated the structure by computational and experimental methods. Mce1R has been shown to harbor the canonical VanR-like structure with a flexible N-terminal 'arm', carrying conserved positively charged residues, most likely involved in the operator DNA binding. The mce1R gene has been cloned, expressed, purified and its DNA-binding activity has been measured in vitro. The Kd value for Mce1R-operator DNA interaction has been determined to be 0.35 ± 0.02 µM which implies that Mce1R binds to DNA with moderate affinity compared to the other FCD family of regulators. So far, this is the first report for measuring the DNA-binding affinity of any VanR-type protein. Despite significant sequence similarity at the N-terminal domain, the wHTH motif of Mce1R exhibits poor conservancy of amino acid residues, critical for DNA-binding, thus results in moderate DNA-binding affinity. The N-terminal DNA-binding domain is structurally dynamic while the C-terminal domain showed significant stability and such profile of structural dynamics is most likely to be preserved in the structural orthologs of Mce1R. In addition to this, a cavity has been detected in the C-terminal domain of Mce1R which contains a few conserved residues. Comparison with other FCD family of regulators suggests that most of the conserved residues might be critical for binding to specific ligand. The max pKd value and drug score for the cavity are estimated to be 9.04 and 109 respectively suggesting that the cavity represents a suitable target site for novel anti-tuberculosis drug discovery approaches.
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Jia P, Xing L, Zhang C, Zhang D, Ma J, Zhao C, Han M, Ren X, An N. MdKNOX19, a class II knotted-like transcription factor of apple, plays roles in ABA signalling/sensitivity by targeting ABI5 during organ development. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 302:110701. [PMID: 33288014 DOI: 10.1016/j.plantsci.2020.110701] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 09/23/2020] [Accepted: 09/30/2020] [Indexed: 05/10/2023]
Abstract
The ABI5 transcription factor, which is a core component of the ABA signaling pathway, affects various plant processes, including seed development and germination and responses to environmental cues. The knotted1-like homeobox (KNOX) transcription factor has crucial functions related to plant development, including the regulation of various hormones. In this study, an ABA-responsive KNOX gene, MdKNOX19, was identified in apple (Malus domestica). The overexpression of MdKNOX19 increased the ABA sensitivity of apple calli, resulting in a dramatic up-regulation in the transcription of the Arabidopsis ABI5-like MdABI5 gene. Additionally, MdKNOX19 overexpression in Micro-Tom adversely affected fruit size and seed yield as well as enhanced ABA sensitivity and up-regulated SlABI5 transcription during seed germination and early seedling development. An examination of MdKNOX19-overexpressing Arabidopsis plants also revealed severe defects in seed development and up-regulated expression of ABA-responsive genes. Furthermore, we further confirmed that MdKNOX19 binds directly to the MdABI5 promoter to activate expression. Our findings suggest MdKNOX19 is a positive regulator of ABI5 expression, and the conserved module MdKNOX19-MdABI5-ABA may contribute to organ development.
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Affiliation(s)
- Peng Jia
- College of Horticulture, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100, China
| | - Libo Xing
- College of Horticulture, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100, China
| | - Chenguang Zhang
- College of Horticulture, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100, China
| | - Dong Zhang
- College of Horticulture, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100, China
| | - Juanjuan Ma
- College of Horticulture, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100, China
| | - Caiping Zhao
- College of Horticulture, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100, China
| | - Mingyu Han
- College of Horticulture, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100, China
| | - Xiaolin Ren
- College of Horticulture, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100, China
| | - Na An
- College of Horticulture, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100, China; College of Life Sciences, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100, China.
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Zhao M, Li C, Ma X, Xia R, Chen J, Liu X, Ying P, Peng M, Wang J, Shi CL, Li J. KNOX protein KNAT1 regulates fruitlet abscission in litchi by repressing ethylene biosynthetic genes. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:4069-4082. [PMID: 32227110 DOI: 10.1093/jxb/eraa162] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 03/27/2020] [Indexed: 05/25/2023]
Abstract
Abscission is triggered by multiple environmental and developmental cues, including endogenous plant hormones. KNOTTED-LIKE HOMEOBOX (KNOX) transcription factors (TFs) play an important role in controlling abscission in plants. However, the underlying molecular mechanism of KNOX TFs in abscission is largely unknown. Here, we identified LcKNAT1, a KNOTTED-LIKE FROM ARABIDOPSIS THALIANA1 (KNAT1)-like protein from litchi, which regulates abscission by modulating ethylene biosynthesis. LcKNAT1 is expressed in the fruit abscission zone and its expression decreases during fruitlet abscission. Furthermore, the expression of the ethylene biosynthetic genes LcACS1, LcACS7, and LcACO2 increases in the fruit abscission zone, in parallel with the emission of ethylene in fruitlets. In vitro and in vivo assays revealed that LcKNAT1 inhibits the expression of LcACS/ACO genes by directly binding to their promoters. Moreover, ectopic expression of LcKNAT1 represses flower abscission in tomatoes. Transgenic plants expressing LcKNAT1 also showed consistently decreased expression of ACS/ACO genes. Collectively, these results indicate that LcKNAT1 represses abscission via the negative regulation of ethylene biosynthesis.
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Affiliation(s)
- Minglei Zhao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, China Litchi Research Center, South China Agricultural University, Guangzhou, China
- Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Caiqin Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, China Litchi Research Center, South China Agricultural University, Guangzhou, China
- Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Xingshuai Ma
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, China Litchi Research Center, South China Agricultural University, Guangzhou, China
- Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Rui Xia
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, China Litchi Research Center, South China Agricultural University, Guangzhou, China
- Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Jianye Chen
- Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Xuncheng Liu
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Peiyuan Ying
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, China Litchi Research Center, South China Agricultural University, Guangzhou, China
- Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Manjun Peng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, China Litchi Research Center, South China Agricultural University, Guangzhou, China
- Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Jun Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, China Litchi Research Center, South China Agricultural University, Guangzhou, China
- Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Chun-Lin Shi
- Section of Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Jianguo Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, China Litchi Research Center, South China Agricultural University, Guangzhou, China
- Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, China
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Feng H, Li X, Chen H, Deng J, Zhang C, Liu J, Wang T, Zhang X, Dong J. GhHUB2, a ubiquitin ligase, is involved in cotton fiber development via the ubiquitin-26S proteasome pathway. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:5059-5075. [PMID: 30053051 PMCID: PMC6184758 DOI: 10.1093/jxb/ery269] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 07/12/2018] [Indexed: 05/02/2023]
Abstract
Cotton fibers, which are extremely elongated single cells of epidermal seed trichomes and have highly thickened cell walls, constitute the most important natural textile material worldwide. However, the regulation of fiber development is not well understood. Here, we report that GhHUB2, a functional homolog of AtHUB2, controls fiber elongation and secondary cell wall (SCW) deposition. GhHUB2 is ubiquitously expressed, including within fibers. Overexpression of GhHUB2 in cotton increased fiber length and SCW thickness, while RNAi knockdown of GhHUB2 resulted in shortened fibers and thinner cell walls. We found that GhHUB2 interacted with GhKNL1, a transcriptional repressor predominantly expressed in developing fibers, and that GhHUB2 ubiquitinated and degraded GhKNL1 via the ubiquitin-26S proteasome pathway. GhHUB2 negatively regulated GhKNL1 protein levels and lead to the disinhibition of genes such as GhXTH1, Gh1,3-β-G, GhCesA4, GhAGP4, GhCTL1, and GhCOBL4, thus promoting fiber elongation and enhancing SCW biosynthesis. We found that GhREV-08, a transcription factor that participates in SCW deposition and auxin signaling pathway, was a direct target of GhKNL1. In conclusion, our study uncovers a novel function of HUB2 in plants in addition to its monoubiquitination of H2B. Moreover, we provide evidence for control of the fiber development by the ubiquitin-26S proteasome pathway.
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Affiliation(s)
- Hao Feng
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xin Li
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Hong Chen
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Jie Deng
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Chaojun Zhang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Ji Liu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Tao Wang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xueyan Zhang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China
| | - Jiangli Dong
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
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Liu Y, You S, Taylor-Teeples M, Li WL, Schuetz M, Brady SM, Douglas CJ. BEL1-LIKE HOMEODOMAIN6 and KNOTTED ARABIDOPSIS THALIANA7 interact and regulate secondary cell wall formation via repression of REVOLUTA. THE PLANT CELL 2014; 26:4843-61. [PMID: 25490916 PMCID: PMC4311193 DOI: 10.1105/tpc.114.128322] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 11/04/2014] [Accepted: 11/17/2014] [Indexed: 05/17/2023]
Abstract
The TALE homeodomain transcription factor KNOTTED ARABIDOPSIS THALIANA7 (KNAT7) is part of a regulatory network governing the commitment to secondary cell wall biosynthesis of Arabidopsis thaliana, where it contributes to negative regulation of this process. Here, we report that BLH6, a BELL1-LIKE HOMEODOMAIN protein, specifically interacts with KNAT7, and this interaction influences secondary cell wall development. BLH6 is a transcriptional repressor, and BLH6-KNAT7 physical interaction enhances KNAT7 and BLH6 repression activities. The overlapping expression patterns of BLH6 and KNAT7 and phenotypes of blh6, knat7, and blh6 knat7 loss-of-function mutants are consistent with the existence of a BLH6-KNAT7 heterodimer that represses commitment to secondary cell wall biosynthesis in interfascicular fibers. BLH6 and KNAT7 overexpression results in thinner interfascicular fiber secondary cell walls, phenotypes that are dependent on the interacting partner. A major impact of the loss of BLH6 and KNAT7 function is enhanced expression of the homeodomain-leucine zipper transcription factor REVOLUTA/INTERFASCICULAR FIBERLESS1 (REV/IFL1). BLH6 and KNAT7 bind to the REV promoter and repress REV expression, while blh6 and knat7 interfascicular fiber secondary cell wall phenotypes are suppressed in blh6 rev and knat7 rev double mutants, suggesting that BLH6/KNAT7 signaling acts through REV as a direct target.
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Affiliation(s)
- Yuanyuan Liu
- Department of Botany, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
| | - Shijun You
- Department of Botany, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
| | - Mallorie Taylor-Teeples
- Department of Plant Biology, UC Davis, Davis, California 95616 Genome Center, UC Davis, Davis, California 95616
| | - Wenhua L Li
- Department of Botany, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
| | - Mathias Schuetz
- Department of Botany, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
| | - Siobhan M Brady
- Department of Plant Biology, UC Davis, Davis, California 95616 Genome Center, UC Davis, Davis, California 95616
| | - Carl J Douglas
- Department of Botany, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
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Testone G, Condello E, Verde I, Nicolodi C, Caboni E, Dettori MT, Vendramin E, Bruno L, Bitonti MB, Mele G, Giannino D. The peach (Prunus persica L. Batsch) genome harbours 10 KNOX genes, which are differentially expressed in stem development, and the class 1 KNOPE1 regulates elongation and lignification during primary growth. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:5417-35. [PMID: 22888130 PMCID: PMC3444263 DOI: 10.1093/jxb/ers194] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The KNOTTED-like (KNOX) genes encode homeodomain transcription factors and regulate several processes of plant organ development. The peach (Prunus persica L. Batsch) genome was found to contain 10 KNOX members (KNOPE genes); six of them were experimentally located on the Prunus reference map and the class 1 KNOPE1 was found to link to a quantitative trait locus (QTL) for the internode length in the peach×Ferganensis population. All the KNOPE genes were differentially transcribed in the internodes of growing shoots; the KNOPE1 mRNA abundance decreased progressively from primary (elongation) to secondary growth (radial expansion). During primary growth, the KNOPE1 mRNA was localized in the cortex and in the procambium/metaphloem zones, whereas it was undetected in incipient phloem and xylem fibres. KNOPE1 overexpression in the Arabidopsis bp4 loss-of-function background (35S:KNOPE1/bp genotype) restored the rachis length, suggesting, together with the QTL association, a role for KNOPE1 in peach shoot elongation. Several lignin biosynthesis genes were up-regulated in the bp4 internodes but repressed in the 35S:KNOPE1/bp lines similarly to the wild type. Moreover, the lignin deposition pattern of the 35S:KNOPE1/bp and the wild-type internodes were the same. The KNOPE1 protein was found to recognize in vitro one of the typical KNOX DNA-binding sites that recurred in peach and Arabidopsis lignin genes. KNOPE1 expression was inversely correlated with that of lignin genes and lignin deposition along the peach shoot stems and was down-regulated in lignifying vascular tissues. These data strongly support that KNOPE1 prevents cell lignification by repressing lignin genes during peach stem primary growth.
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Affiliation(s)
- Giulio Testone
- Institute of Agricultural Biology and Biotechnology, National Research Council of Italy (CNR), via Salaria km 29,300, 00015, Monterotondo Scalo, Rome, Italy
- These authors contributed equally to this work
| | - Emiliano Condello
- Fruit Tree Research Centre, Agriculture Research Council (CRA), Via di Fioranello 52, 00134 Rome, Italy
- These authors contributed equally to this work
| | - Ignazio Verde
- Fruit Tree Research Centre, Agriculture Research Council (CRA), Via di Fioranello 52, 00134 Rome, Italy
| | - Chiara Nicolodi
- Institute of Agricultural Biology and Biotechnology, National Research Council of Italy (CNR), via Salaria km 29,300, 00015, Monterotondo Scalo, Rome, Italy
| | - Emilia Caboni
- Fruit Tree Research Centre, Agriculture Research Council (CRA), Via di Fioranello 52, 00134 Rome, Italy
| | - Maria Teresa Dettori
- Fruit Tree Research Centre, Agriculture Research Council (CRA), Via di Fioranello 52, 00134 Rome, Italy
| | - Elisa Vendramin
- Fruit Tree Research Centre, Agriculture Research Council (CRA), Via di Fioranello 52, 00134 Rome, Italy
| | - Leonardo Bruno
- Department of Ecology, University of Calabria, Ponte Bucci, 87030 Arcavacata di Rende, Cosenza, Italy
| | - Maria Beatrice Bitonti
- Department of Ecology, University of Calabria, Ponte Bucci, 87030 Arcavacata di Rende, Cosenza, Italy
| | - Giovanni Mele
- Institute of Agricultural Biology and Biotechnology, National Research Council of Italy (CNR), via Salaria km 29,300, 00015, Monterotondo Scalo, Rome, Italy
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Abstract
In the following chapter we describe methods and protocols to analyze the interaction of proteins with DNA using footprinting and related techniques based on the modification of DNA with either hydroxyl radicals or methylating agents. Footprinting, based on the protection from chemical modification of DNA through the specific binding of a protein, gives information about the nucleotides that are in close contact with the protein upon binding. The derived missing nucleoside and interference techniques identify nucleotides that are energetically important for protein binding. These methods are highly valuable to study in detail the interaction of a transcription factor with nucleotides on both strands of its target DNA sequence.
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Takano S, Niihama M, Smith HMS, Tasaka M, Aida M. gorgon, a Novel Missense Mutation in the SHOOT MERISTEMLESS Gene, Impairs Shoot Meristem Homeostasis in Arabidopsis. ACTA ACUST UNITED AC 2010; 51:621-34. [DOI: 10.1093/pcp/pcq028] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Bolduc N, Hake S. The maize transcription factor KNOTTED1 directly regulates the gibberellin catabolism gene ga2ox1. THE PLANT CELL 2009; 21:1647-58. [PMID: 19567707 PMCID: PMC2714931 DOI: 10.1105/tpc.109.068221] [Citation(s) in RCA: 196] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Revised: 05/31/2009] [Accepted: 06/08/2009] [Indexed: 05/18/2023]
Abstract
KNOTTED1 (KN1)-like homeobox (KNOX) transcription factors are involved in the establishment and maintenance of plant meristems; however, few direct targets of KNOX proteins have been recognized. Using a combination of double mutant analysis and biochemistry, we found that in maize (Zea mays), KN1 negatively modulates the accumulation of gibberellin (GA) through the control of ga2ox1, which codes for an enzyme that inactivates GA. The ga2ox1 mRNA level is elevated in immature leaves of dominant KNOX mutants and downregulated in reproductive meristems of the null allele kn1-e1. KN1 binds in vivo to an intron of ga2ox1 through a cis-regulatory element containing two TGAC motifs. VP16-KN1 activates transcription in planta from a chimeric promoter containing this binding site. The domains of expression of kn1 and ga2ox1 mRNAs overlap at the base of the shoot apical meristem and the base of newly initiated leaves, suggesting that KN1-mediated activation of ga2ox1 maintains a boundary between meristem cell identity and rapidly elongating cells of the shoot. The KN1 binding site is conserved in ga2ox1 genes of different grasses, suggesting that the local regulation of bioactive GA levels through KNOX proteins is a common theme in grasses.
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Affiliation(s)
- Nathalie Bolduc
- Plant Gene Expression Center, U.S. Department of Agriculture-Agricultural Research Service, University of California, Albany, California 94710, USA
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Bolduc N, Hake S, Jackson D. Dual functions of the KNOTTED1 homeodomain: sequence-specific DNA binding and regulation of cell-to-cell transport. Sci Signal 2008; 1:pe28. [PMID: 18544748 DOI: 10.1126/scisignal.123pe28] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Homeodomain proteins are well-characterized developmental regulators that control expression of target genes through sequence-specific DNA binding. The homeodomain forms a trihelical structure, with the third helix conferring specific interactions with the DNA major groove. A specific class of plant homeodomain proteins, called KNOX [KNOTTED1 (KN1)-like homeobox], also has the ability to signal between cells by directly trafficking through intercellular channels called plasmodesmata. Trafficking is mediated by a signal that is also contained within the homeodomain. Movement protein binding protein 2C was identified as a protein that interacts with the KN1 homeodomain and regulates the cell-to-cell trafficking of KN1 by sequestering the protein on microtubules. Therefore, KN1 has multiple potential cellular addresses, each of which is conferred by its homeodomain.
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Affiliation(s)
- Nathalie Bolduc
- Plant Gene Expression Center, 800 Buchanan Street, Albany, CA 94710, USA
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Viola IL, Gonzalez DH. Interaction of the BELL-like protein ATH1 with DNA: role of homeodomain residue 54 in specifying the different binding properties of BELL and KNOX proteins. Biol Chem 2006; 387:31-40. [PMID: 16497162 DOI: 10.1515/bc.2006.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We have studied the interaction of the BELL-like Arabidopsis homeodomain protein ATH1 with DNA. Analysis of oligonucleotides selected by the ATH1 homeodomain from a random mixture suggests that ATH1 preferentially binds the sequence TGACAGGT. Single nucleotide replacements at positions 2 or 3 of this sequence abolish binding, while changes at position 4 are more tolerated. Changes outside this core differentially affect binding, depending on the position. Hydroxyl radical footprinting and missing nucleoside experiments showed that ATH1 interacts with a 7-bp region of the strand carrying the GAC core. On the other strand, protection was observed over a 7-bp region, comprising one additional nucleotide complementary to T in position 1. A comparative analysis of the binding preferences of the homeodomains of ATH1 and STM (a KNOX homeodomain protein) indicated that they bind similar sequences, but with differences in affinity and specificity. The decreased affinity displayed by the ATH1 homeodomain correlates with the presence of valine (instead of lysine as in STM) at position 54. This difference also explains the decreased and increased selectivities, respectively, at positions 4 and 5. Our results point to an essential role of residue 54 in determining the different binding properties of BELL and KNOX homeodomains.
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Affiliation(s)
- Ivana L Viola
- Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, CC 242 Paraje El Pozo, 3000 Santa Fe, Argentina
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