Purification and properties of an endospermic protein of maize associated with the Opaque-2 and Opaque-6 genes

Fonzo, N. di; Manzocchi, Lucia A.; Salamini, F.; Soave, C.

doi:10.1007/bf00391237

Cited by 28 publications

(21 citation statements)

References 16 publications

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“…O2 encodes a bZIP transcription factor (Schmidt et al, 1990) that activates expression of 22-kD a-zeins (Muth et al, 1996) and the 14-kD b-zein (Cord Neto et al, 1995). The first characterized nonzein target of O2 is the b-32 gene (Di Fonzo et al, 1986), which is associated with the defense against fungal pathogens (Ferreira et al, 2007). The cyPPDK1 gene, which is involved in carbon and amino acid metabolism, was also identified as directly regulated by O2 (Sheen, 1991;Maddaloni et al, 1996).…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies indicated that O2 directly regulates a number of genes encoding nonzein proteins, including b-32 (Di Fonzo et al, 1986), which encodes a ribosome inactivating protein involved in pathogen defense. O2 is capable of activating b-32 gene expression by interacting with five binding sites (B1-B5), but only the B5 site contains the ACGT core sequence (Lohmer et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

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Genome-Wide Characterization ofcis-Acting DNA Targets Reveals the Transcriptional Regulatory Framework ofOpaque2in Maize

et al. 2015

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Opaque2 (O2) is a transcription factor that plays important roles during maize endosperm development. Mutation of the O2 gene improves the nutritional value of maize seeds but also confers pleiotropic effects that result in reduced agronomic quality. To reveal the transcriptional regulatory framework of O2, we studied the transcriptome of o2 mutants using RNA sequencing (RNA-Seq) and determined O2 DNA binding targets using chromatin immunoprecipitation coupled to highthroughput sequencing (ChIP-Seq). The RNA-Seq analysis revealed 1605 differentially expressed genes (DEGs) and 383 differentially expressed long, noncoding RNAs. The DEGs cover a wide range of functions related to nutrient reservoir activity, nitrogen metabolism, stress resistance, etc. ChIP-Seq analysis detected 1686 O2 DNA binding sites distributed over 1143 genes. Overlay of the RNA-Seq and ChIP-Seq results revealed 35 O2-modulated target genes. We identified four O2 binding motifs; among them, TGACGTGG appears to be the most conserved and strongest. We confirmed that, except for the 16-and 18-kD zeins, O2 directly regulates expression of all other zeins. O2 directly regulates two transcription factors, genes linked to carbon and amino acid metabolism and abiotic stress resistance. We built a hierarchical regulatory model for O2 that provides an understanding of its pleiotropic biological effects.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Genome-Wide Characterization ofcis-Acting DNA Targets Reveals the Transcriptional Regulatory Framework ofOpaque2in Maize

et al. 2015

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“…Different from the Binding Sites in the b-32 Gene 0 2 plays a role in regulating the expression of another endosperm protein, b-32 (Soave et al, 1981;Di Fonzo et al, 1986;Manzocchi et al, 1986). The b-32 gene encodes a water-soluble 32-kD albumin that accumulates in the cytosol during endosperm development (Soave et al, 1981;Di Fonzo et al, 1986).…”

Section: The 0 2 Binding Site Sequence In 22-kd Zein Genes 1smentioning

confidence: 99%

“…The b-32 gene encodes a water-soluble 32-kD albumin that accumulates in the cytosol during endosperm development (Soave et al, 1981;Di Fonzo et al, 1986). In 02 mutants, the leve1 of b-32 mRNA is reduced to 5 to 10% of wild-type levels.…”

Section: The 0 2 Binding Site Sequence In 22-kd Zein Genes 1smentioning

confidence: 99%

Opaque-2 is a transcriptional activator that recognizes a specific target site in 22-kD zein genes.

et al. 1992

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opaque-2 (02) is a regulatory locus in maize that plays an essential role in controlling the expression of genes encoding the 22-kD zein proteins. Through DNase I footprinting and DNA binding analyses, we have identified the binding site for the 0 2 protein (02) in the promoter of 22-kD zein genes. The sequence in the 22-kD zein gene promoter that is recognized by 0 2 is similar to the target site recognized by other "basiclleucine zipper" (bZIP) proteins in that it contains an ACGT core that is necessary for DNA binding. The site is located in the -300 region relative to the translation start and lies about 20 bp downstream of the highly conserved zein gene sequence motif known as the "prolamin box." Employing gel mobility shift assays, we used 0 2 antibodies and nuclear extracts from an 02 null mutant to demonstrate that the 0 2 protein in maize endosperm nuclei recognizes the target site in the zein gene promoter. Mobility shift assays using nuclear proteins from an 02 null mutant indicated that other endosperm proteins in addition to 0 2 can bind the 02 target site and that 0 2 may be associated with one of these proteins. We also demonstrated that in yeast cells the 0 2 protein can activate expression of a lacZ gene containing a multimer of the 0 2 target sequence as part of its promoter, thus confirming its role as a transcriptional activator. A computer-assisted search indicated that the 0 2 target site is not present in the promoters of zein genes other than those of the 22-kD class. These data suggest a likely explanation at the molecular leve1 for the differential effect of 02 mutations on expression of certain members of the zein gene family.

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“…Vol. 107, 1995 unknown function (DiFonzo et al, 1986(DiFonzo et al, , 1988Lohmer et al, 1991). Bass et al (1992) subsequently reported low levels of RIP activity associated with preparations of b-32.…”

Section: Cv4 7al United Kingdom (Mh)mentioning

confidence: 99%

Maize Ribosome-Inactivating Protein (b-32) (Homologs in Related Species, Effects on Maize Ribosomes, and Modulation of Activity by Pro-Peptide Deletions)

Hey¹,

Hartley²,

Walsh³

1995

Plant Physiol.

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The ribosome-inactivating protein (RIP) from maize (Zea mays L.) is unusual in that it i s produced in the endosperm as an inactive pro-form, also known as b-32, which can be converted by limited proteolysis to a two-chain active form, cup RIP. lmmunological analysis of seed extracts from a variety of species related to maize showed that pro/cup forms of RIP are not unique to maize but are also found in other members of the Panicoideae, including Tripacum and sorghum. Ribosomes isolated from maize were quite resistant to both purified pro-and ap maize RIPs, whereas they were highly susceptible to the RIP from pokeweed. This suggests that the production of an inactive pro-RIP is nota mechanism to protect the plant's own ribosomes from deleterious action of the ap RIP. RIP derivatives with various pro-segments removed were expressed at high levels in Fscherichia coli. Measurement of their activity before and after treatment with subtilisin Carlsberg clearly identified the 25-amino acid intradomain insertion, rather than the N-or Cterminal extensions, as the major element responsible for suppression of enzymatic activity. A RIP with all three processed regions deleted had activity close to that of the native a@ form.Many plants produce RIPs, a unique class of proteins that are exceptionally potent inhibitors of eukaryotic protein synthesis (Stirpe et al., 1992;. RIPs catalytically inactivate eukaryotic, and in some cases prokaryotic, ribosomes by cleaving the N-glycosyl bond of a single specific adenine residue in the ribosomal RNA (A,,,4 in the case of rat liver ribosomes; Endo et al., 1988). Depending on the species of plant, RIPs can be expressed in leaves, roots, sap, or seeds, often at very high levels. The physiological function of RIPs is at present unclear, although evidence is accumulating that they have a role in plant defense. Leah et al. (1991) have shown that a RIP from barley seeds inhibits the growth of fungal pathogens, particularly when combined with seed chitinases and glucanases. A defensive role against the mechanical transmission of plant viruses has also been proposed Bonness et al., 1994). These results have been extended by the observation that transgenic tobacco plants expressing a RIP from barley exhibit increased tolerance to fungal infection (Logemann et al., 1992), and plants exCorresponding author; fax 1-317-337-3228. CV4 7AL, United Kingdom (M.H.)pressing a RIP from pokeweed have decreased susceptibility to vira1 infection (Lodge et al., 1993).RIPs have been classified into two types (Stirpe et al., 1992): type-1 RIPs are the most prevalent; over 40 have been described. They are typically single-chain, basic polypeptides of 25 to 32 kD with relatively low toxicity to intact cells because they do not readily cross cellular membranes. The rarer type-2 RIPs have arisen from a gene fusion between a type-1 RIP domain and a lectin-like domain. The lectin domain (or B chain) can bind to cell surfaces and mediate the delivery of the RIP (or A chain) into the cytosol of the cell. The RIP A ch...

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Purification and properties of an endospermic protein of maize associated with the Opaque-2 and Opaque-6 genes

Cited by 28 publications

References 16 publications

Genome-Wide Characterization ofcis-Acting DNA Targets Reveals the Transcriptional Regulatory Framework ofOpaque2in Maize

Genome-Wide Characterization ofcis-Acting DNA Targets Reveals the Transcriptional Regulatory Framework ofOpaque2in Maize

Opaque-2 is a transcriptional activator that recognizes a specific target site in 22-kD zein genes.

Maize Ribosome-Inactivating Protein (b-32) (Homologs in Related Species, Effects on Maize Ribosomes, and Modulation of Activity by Pro-Peptide Deletions)

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