Identification of functional domains in the maize transcriptional activator C1: comparison of wild-type and dominant inhibitor proteins.

Goff, Stephen A.; Cone, Karen C.; Fromm, Michael

doi:10.1101/gad.5.2.298

Cited by 137 publications

(78 citation statements)

References 72 publications

(98 reference statements)

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“…Transient transformation of intact plant organs by particle bombardment has proven to be a powerful technique to study the transcriptional regulation of organspecific genes, since the transformed cells can be monitored in their native organ environment (23,24). Since ballistic transient transformation has the advantage of rapidity of analysis, compared with the stable transformation of plants with the large numbers of promoter-reporter gene constructs necessary for detailed cis-analysis, we applied this technique to analysis of the cucumisin promoter.…”

Section: Discussionmentioning

confidence: 99%

TGTCACA Motif Is a Novel cis-Regulatory Enhancer Element Involved in Fruit-specific Expression of the cucumisin Gene

Yamagata

Yonesu

Hirata

et al. 2002

Journal of Biological Chemistry

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Cucumisin, a subtilisin-like serine protease, is expressed at high levels in the fruit of melon (Cucumis melo L.) and accumulates in the juice. We investigated roles of the promoter regions and DNA-protein interactions in fruit-specific expression of the cucumisin gene. In transient expression analysis, a chimeric gene construct containing a 1.2-kb cucumisin promoter fused to a ␤-glucuronidase (GUS) reporter gene was expressed in fruit tissues at high levels, but the promoter activities in leaves and stems were very low. Deletion analysis indicated that a positive regulatory region is located between nucleotides ؊234 and ؊214 relative to the transcriptional initiation site. Gain-of-function experiments revealed that this 20-bp sequence conferred fruit specificity and contained a regulatory enhancer. Gel mobility shift experiments demonstrated the presence of fruit nuclear factors that interact with the cucumisin promoter. A typical G-box (GACACGTGTC) present in the 20-bp sequence did not bind fruit protein, but two possible cis-elements, an I-box-like sequence (AGATAT-GATAAAA) and an odd base palindromic TGTCACA motif, were identified in the promoter region between positions ؊254 and ؊215. The I-box-like sequence bound more tightly to fruit nuclear protein than the TGTCACA motif. The I-box-like sequence functions as a negative regulatory element, and the TGTCACA motif is a novel enhancer element necessary for fruit-specific expression of the cucumisin gene. Specific nucleotides responsible for the binding of fruit nuclear protein in these two elements were also determined.Timing and levels of gene expression are critical to the proper development of eukaryotic organisms. Regulation of the expression pattern of a particular gene can involve the specific binding of trans-acting factors to the cognate cis-elements, constituting a crucial step in transcriptional initiation and, in turn, on the spatial and temporal expression of genes. Plant genes that show tissue specificity, developmental specificity, and a wide range of expression levels have been characterized, whereas their expression patterns are also influenced by environmental stimuli. A family of genes for fruit proteins provide a model system for the study of the regulatory mechanisms of plant genes, since their expression is restricted to a specific tissue and stage during fruit development (1). A number of fruit-specific genes that are activated during ripening have been isolated from tomato and other fruits, and genes responding to ethylene and nonethylene signals have been identified (1, 2). The promoters of fruit-specific genes would also be of great interest for use in strategies to manipulate fruit metabolism and produce valuable proteins such as antibody, biopharmaceuticals, and edible vaccines through methods of genetic engineering (3-5). However, the detailed mechanisms by which the expression of fruit protein genes are regulated are poorly understood, as many of the essential cis-elements have not been identified.Melon cucumisin, an extracellular...

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Section: Discussionmentioning

confidence: 99%

TGTCACA Motif Is a Novel cis-Regulatory Enhancer Element Involved in Fruit-specific Expression of the cucumisin Gene

Yamagata

Yonesu

Hirata

et al. 2002

Journal of Biological Chemistry

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“…Previous studies of C1 have demonstrated that its carboxyterminal 100 amino acids function as a transcriptional activation domain in maize and the yeast Saccharomyces cerevisiae when fused to the DNA-binding domain of the yeast GAL4 regulator (15). In addition, when the carboxy-terminal region of otherwise native C1 was replaced by the GAL4 transcriptional activation domain, the resulting fusion protein activated specific anthocyanin promoters and the entire biosynthetic pathway in maize cells but still required the B protein (15).…”

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confidence: 99%

Extensive Mutagenesis of a Transcriptional Activation Domain Identifies Single Hydrophobic and Acidic Amino Acids Important for Activation In Vivo

Sainz

Goff

Chandler

1997

Molecular and Cellular Biology

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C1 is a transcriptional activator of genes encoding biosynthetic enzymes of the maize anthocyanin pigment pathway. C1 has an amino terminus homologous to Myb DNA-binding domains and an acidic carboxyl terminus that is a transcriptional activation domain in maize and yeast cells. To identify amino acids critical for transcriptional activation, an extensive random mutagenesis of the C1 carboxyl terminus was done. The C1 activation domain is remarkably tolerant of amino acid substitutions, as changes at 34 residues had little or no effect on transcriptional activity. These changes include introduction of helix-incompatible amino acids throughout the C1 activation domain and alteration of most single acidic amino acids, suggesting that a previously postulated amphipathic ␣-helix is not required for activation. Substitutions at two positions revealed amino acids important for transcriptional activation. Replacement of leucine 253 with a proline or glutamine resulted in approximately 10% of wild-type transcriptional activation. Leucine 253 is in a region of C1 in which several hydrophobic residues align with residues important for transcriptional activation by the herpes simplex virus VP16 protein. However, changes at all other hydrophobic residues in C1 indicate that none are critical for C1 transcriptional activation. The other important amino acid in C1 is aspartate 262, as a change to valine resulted in only 24% of wild-type transcriptional activation. Comparison of our C1 results with those from VP16 reveal substantial differences in which amino acids are required for transcriptional activation in vivo by these two acidic activation domains.

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“…Although TGA1a has been deduced to activate transcription by increasing the number of pre-initiation complexes in a human in vitro transcription system , the molecular mechanisms for activation are not as clear in other factors. The Pro-rich region of Arabidopsis GBF1 (Schindler et al 1992b) and the acidic regions of maize VP1 (McCarty et al 1991), C1 (Goff et al 1991), and rice OSH42 (Tamaoki et al 1995) have been identified in each molecule and can activate transcription even after combining separately with a heterologous DNA-binding domain. We found that the E3 region of the HALF-1 protein and its corresponding region of Arabidopsis GBF1 are able to activate transcription.…”

Section: Discussionmentioning

confidence: 99%

“…In contrast, there are only a few reports showing an activation domain or a region responsible for the activation of plant transcription factors, e.g. the Prorich region of Arabidopsis GBF1 (Schindler et al 1992b), the acidic regions of maize VP1 (McCarty et al 1990) and C1 (Goff et al 1991) and rice OSH42 (Tamaoki et al 1995), and little is known about the molecular mechanisms of transcriptional activation in plants.…”

Section: Introductionmentioning

confidence: 99%

HALF‐1, a bZIP‐type protein, interacting with the wheat transcription factor HBP‐1a contains a novel transcriptional activation domain

et al. 1996

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Background: Nuclear factors bind to cis-acting elements and mediate transcriptional regulation through protein-protein interactions with other factors. The bZIP-type wheat nuclear protein HBP-1a(17) is a putative transcriptional activator specifically binding to the Hex (ccACGTCA) and Gbox (CCACGTGG) motifs, which are often found in the cis-acting elements critical for various responses in plants.

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Identification of functional domains in the maize transcriptional activator C1: comparison of wild-type and dominant inhibitor proteins.

Cited by 137 publications

References 72 publications

TGTCACA Motif Is a Novel cis-Regulatory Enhancer Element Involved in Fruit-specific Expression of the cucumisin Gene

TGTCACA Motif Is a Novel cis-Regulatory Enhancer Element Involved in Fruit-specific Expression of the cucumisin Gene

Extensive Mutagenesis of a Transcriptional Activation Domain Identifies Single Hydrophobic and Acidic Amino Acids Important for Activation In Vivo

HALF‐1, a bZIP‐type protein, interacting with the wheat transcription factor HBP‐1a contains a novel transcriptional activation domain

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