Corrigendum: BEL1-like Homeodomain Protein BLH6a Is a Negative Regulator of CAld5H2 in Sinapyl Alcohol Monolignol Biosynthesis in Poplar

Lignin is one of the major components of xylem cell walls in tree stems. The lignin in the wood of most flowering plants (dicotyledonous angiosperms) is typically polymerized from three monolignol precursors, coniferyl alcohol, sinapyl alcohol, and p-coumaroyl alcohol, resulting in guaiacyl (G), syringyl (S), and hydroxyphenyl (H) subunits, respectively. In this study, we focus on the transcriptional regulation of a coniferaldehyde 5-hydroxylase (CAld5H2) gene, which encodes a key enzyme for sinapyl alcohol biosynthesis. We carried out a yeast one-hybrid (Y1H) screen to identify candidate upstream transcription factors (TFs) regulating CAld5H2. We obtained 12 upstream TFs as potential regulators of CAld5H2. One of these TF genes, BLH6a, encodes a BEL1-like homeodomain (BLH) protein and negatively regulated the CAld5H2 promoter activity. The direct regulation of CAld5H2 promoter by BLH6a was supported by chromatin immunoprecipitation–quantitative polymerase chain reaction (ChIP–qPCR) and dominant repression of BLH6a in transgenic plants. Luciferase complementation imaging analyses showed extensive protein–protein interactions among these 12 TFs. We propose that BLH6a is a negative regulator of CAld5H2, which acts through combinatorial regulation of multiple TFs for sinapyl alcohol (S monolignol) biosynthesis in poplar.

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Cux/CDP Homeoprotein Is a Component of NF-μNR and Represses the Immunoglobulin Heavy Chain Intronic Enhancer by Antagonizing the Bright Transcription Activator

Molecular and Cellular Biology ◽

10.1128/mcb.19.1.284 ◽

1999 ◽

Vol 19 (1) ◽

pp. 284-295 ◽

Cited By ~ 52

Author(s):

Zhiyong Wang ◽

Adrian Goldstein ◽

Rui-Ting Zong ◽

Danjun Lin ◽

Ellis J. Neufeld ◽

...

Keyword(s):

B Cells ◽

Heavy Chain ◽

Nuclear Matrix ◽

Binding Sites ◽

Immunoglobulin Heavy Chain ◽

Negative Regulator ◽

Homeodomain Protein ◽

Transcription Activator ◽

Expression Library ◽

Intronic Enhancer

ABSTRACT Nuclear matrix attachment regions (MARs) flanking the immunoglobulin heavy chain intronic enhancer (Eμ) are the targets of the negative regulator, NF-μNR, found in non-B and early pre-B cells. Expression library screening with NF-μNR binding sites yielded a cDNA clone encoding an alternatively spliced form of the Cux/CDP homeodomain protein. Cux/CDP fulfills criteria required for NF-μNR identity. It is expressed in non-B and early pre-B cells but not mature B cells. It binds to NF-μNR binding sites within Eμ with appropriate differential affinities. Antiserum specific for Cux/CDP recognizes a polypeptide of the predicted size in affinity-purified NF-μNR preparations and binds NF-μNR complexed with DNA. Cotransfection with Cux/CDP represses the activity of Eμ via the MAR sequences in both B and non-B cells. Cux/CDP antagonizes the effects of the Bright transcription activator at both the DNA binding and functional levels. We propose that Cux/CDP regulates cell-type-restricted, differentiation stage-specific Eμ enhancer activity by interfering with the function of nuclear matrix-bound transcription activators.

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ERK1/2 is a negative regulator of homeodomain protein Arix/Phox2a

Journal of Neurochemistry ◽

10.1111/j.1471-4159.2005.03333.x ◽

2005 ◽

Vol 94 (6) ◽

pp. 1719-1727 ◽

Cited By ~ 8

Author(s):

Marlene M. Hsieh ◽

George Lupas ◽

Jennifer Rychlik ◽

Suzan Dziennis ◽

Beth A. Habecker ◽

...

Keyword(s):

Negative Regulator ◽

Homeodomain Protein

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Functional analysis of the nuclear LIM domain interactor NLI.

Molecular and Cellular Biology ◽

10.1128/mcb.17.10.5688 ◽

1997 ◽

Vol 17 (10) ◽

pp. 5688-5698 ◽

Cited By ~ 118

Author(s):

L W Jurata ◽

G N Gill

Keyword(s):

Transcriptional Activation ◽

Negative Regulator ◽

Homeodomain Protein ◽

Lim Domain ◽

Transcriptional Responses ◽

Amino Terminal ◽

High Affinity ◽

Lim Domains ◽

Lim Homeodomain

LIM homeodomain and LIM-only (LMO) transcription factors contain two tandemly arranged Zn2+-binding LIM domains capable of mediating protein-protein interactions. These factors have restricted patterns of expression, are found in invertebrates as well as vertebrates, and are required for cell type specification in a variety of developing tissues. A recently identified, widely expressed protein, NLI, binds with high affinity to the LIM domains of LIM homeodomain and LMO proteins in vitro and in vivo. In this study, a 38-amino-acid fragment of NLI was found to be sufficient for the association of NLI with nuclear LIM domains. In addition, NLI was shown to form high affinity homodimers through the amino-terminal 200 amino acids, but dimerization of NLI was not required for association with the LIM homeodomain protein Lmxl. Chemical cross-linking analysis revealed higher-order complexes containing multiple NLI molecules bound to Lmx1, indicating that dimerization of NLI does not interfere with LIM domain interactions. Additionally, NLI formed complexes with Lmx1 on the rat insulin I promoter and inhibited the LIM domain-dependent synergistic transcriptional activation by Lmx1 and the basic helix-loop-helix protein E47 from the rat insulin I minienhancer. These studies indicate that NLI contains at least two functionally independent domains and may serve as a negative regulator of synergistic transcriptional responses which require direct interaction via LIM domains. Thus, NLI may regulate the transcriptional activity of LIM homeodomain proteins by determining specific partner interactions.

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The Last Step of Syringyl Monolignol Biosynthesis in Angiosperms Is Regulated by a Novel Gene Encoding Sinapyl Alcohol Dehydrogenase

The Plant Cell ◽

10.2307/3871387 ◽

2001 ◽

Vol 13 (7) ◽

pp. 1567 ◽

Cited By ~ 3

Author(s):

Laigeng Li ◽

Xiao Fei Cheng ◽

Jacqueline Leshkevich ◽

Toshiaki Umezawa ◽

Scott A. Harding ◽

...

Keyword(s):

Alcohol Dehydrogenase ◽

Gene Encoding ◽

Sinapyl Alcohol ◽

Novel Gene ◽

Monolignol Biosynthesis

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The Last Step of Syringyl Monolignol Biosynthesis in Angiosperms Is Regulated by a Novel Gene Encoding Sinapyl Alcohol Dehydrogenase

The Plant Cell ◽

10.1105/tpc.13.7.1567 ◽

2001 ◽

Vol 13 (7) ◽

pp. 1567-1586 ◽

Cited By ~ 124

Author(s):

L. Li

Keyword(s):

Alcohol Dehydrogenase ◽

Gene Encoding ◽

Sinapyl Alcohol ◽

Novel Gene ◽

Monolignol Biosynthesis

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Forced expression of the homeodomain protein Gax inhibits cardiomyocyte proliferation and perturbs heart morphogenesis

Development ◽

10.1242/dev.124.21.4405 ◽

1997 ◽

Vol 124 (21) ◽

pp. 4405-4413 ◽

Cited By ~ 2

Author(s):

S.A. Fisher ◽

E. Siwik ◽

D. Branellec ◽

K. Walsh ◽

M. Watanabe

Keyword(s):

Cell Cycle ◽

Heart Development ◽

Negative Regulator ◽

Homeodomain Protein ◽

Cardiomyocyte Proliferation ◽

Heart Morphogenesis ◽

Chicken Heart ◽

Nuclear Expression ◽

Compact Zone ◽

Myocyte Proliferation

The development of the tubular heart into a complex four-chambered organ requires precise temporal and region-specific regulation of cell proliferation, migration, death and differentiation. While the regulatory mechanisms in heart morphogenesis are not well understood, increasing attention has focused on the homeodomain proteins, which are generally linked to morphogenetic processes. The homeodomain containing gene Gax has been shown to be expressed in heart and smooth muscle tissues. In this study, the Gax protein was detected in the nuclei of myocardial cells relatively late in chicken heart development, at a time when myocyte proliferation is declining. To test the hypothesis that the Gax protein functions as a negative regulator of cardiomyocyte proliferation, a replication-defective adenovirus was used to force its precocious nuclear expression during chicken heart morphogenesis. In experiments in which Gax- and beta-galactosidase-expressing adenoviruses were co-injected, clonal expansion of myocytes was reduced, consistent with inhibition of myocyte proliferation. This effect on proliferation was corroborated by the finding that the percentage of exogenous Gax-expressing myocytes that were positive for the cell cycle marker PCNA decreased over time and was lower than in control myocytes. The precocious nuclear expression of Gax in tubular hearts resulted in abnormal heart morphology, including small ventricles with rounded apices, a thinned compact zone and coarse trabeculae. These results suggest a role for the Gax protein in heart morphogenesis causing proliferating cardiomyocytes to withdraw from the cell cycle, thus influencing the size and shape that the heart ultimately attains.

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