An opaque mutation was identified that reduces γ-zein synthesis in maize endosperm. The mutation,... more An opaque mutation was identified that reduces γ-zein synthesis in maize endosperm. The mutation, opaque-15, causes a 2- to 3-fold reduction in γ-zein mRNA and protein synthesis and reduces the proportion of the 27-kDa γ-zein A gene transcript. Although the protein bodies in opaque-15 are similar in size and morphology compared to wild type, there are fewer of them in developing endosperm cells. The opaque-15 mutation maps near the telomere of chromosome 7L, coincident with an opaque-2 modifier locus. Based on its phenotype, opaque-15 appears to be a mutation of an opaque-2 modifier gene.
The invention provides isolated nucleic acids and their encoded proteins that are involved in cel... more The invention provides isolated nucleic acids and their encoded proteins that are involved in cell cycle regulation. The invention further provides recombinant expression cassettes, host cells, transgenic plants, and antibody compositions. The present invention provides methods and compositions relating to altering cell cycle protein content, cell cycle progression, cell number and/or composition of plants.
Lysine is the most limiting essential amino acid in cereals, and for many years plant breeders ha... more Lysine is the most limiting essential amino acid in cereals, and for many years plant breeders have attempted to increase its concentration to improve the nutritional quality of these grains. The opaque2 mutation in maize doubles the lysine content in the endosperm, but the mechanism by which this occurs is unknown. We show that elongation factor 1 alpha (EF-1 alpha) is overexpressed in opaque2 endosperm compared with its normal counterpart and that there is a highly significant correlation between EF-1 alpha concentration and the total lysine content of the endosperm. This relationship is also true for two other cereals, sorghum and barley. It appears that genetic selection for genotypes with a high concentration of EF-1 alpha can significantly improve the nutritional quality of maize and other cereals.
The invention provides novel methods of using viral replicase polypeptides and polynucleotides. I... more The invention provides novel methods of using viral replicase polypeptides and polynucleotides. Included are methods for increasing transformation frequencies, increasing crop yield, providing a positive growth advantage, modulating cell division, transiently modulating cell division, and for providing a means of positive selection.
The endoreduplication cell cycle is a variant of the standard mitotic cell cycle in which reitera... more The endoreduplication cell cycle is a variant of the standard mitotic cell cycle in which reiterated rounds of DNA synthesis occur in the absence of chromosome segregation and cell division. The resulting polyploid cells are frequently found in plants and often occur in tissues with a high metabolic activity that accumulate storage molecules. In this chapter we review the current understanding of
Maize endosperm development is characterized by three distinct types of cell cycles: i) acytokine... more Maize endosperm development is characterized by three distinct types of cell cycles: i) acytokinetic mitosis during the coenocyte stage; ii) mitosis followed by cytokinesis during the mitotic stage; and iii) DNA replication without mitosis or cytokinesis during the endoreduplication stage. Although the molecular mechanisms controlling the transition between these different types of cell cycles are not fully understood, considerable progress is being made in the identification of key cell cycle regulators from model plant systems, and cereals in particular. This research is providing new insights into the importance of cell cycle regulation during the development of the maize endosperm. Traditional maize mutants with defective endosperms and the more recently available transposon-tagged mutants offer the opportunity to identify key regulators of cell division and endosperm development. In addition, transgenic approaches are being applied to unravel the relative contributions of cell ...
An opaque mutation was identified that reduces γ-zein synthesis in maize endosperm. The mutation,... more An opaque mutation was identified that reduces γ-zein synthesis in maize endosperm. The mutation, opaque-15, causes a 2- to 3-fold reduction in γ-zein mRNA and protein synthesis and reduces the proportion of the 27-kDa γ-zein A gene transcript. Although the protein bodies in opaque-15 are similar in size and morphology compared to wild type, there are fewer of them in developing endosperm cells. The opaque-15 mutation maps near the telomere of chromosome 7L, coincident with an opaque-2 modifier locus. Based on its phenotype, opaque-15 appears to be a mutation of an opaque-2 modifier gene.
The invention provides isolated nucleic acids and their encoded proteins that are involved in cel... more The invention provides isolated nucleic acids and their encoded proteins that are involved in cell cycle regulation. The invention further provides recombinant expression cassettes, host cells, transgenic plants, and antibody compositions. The present invention provides methods and compositions relating to altering cell cycle protein content, cell cycle progression, cell number and/or composition of plants.
Lysine is the most limiting essential amino acid in cereals, and for many years plant breeders ha... more Lysine is the most limiting essential amino acid in cereals, and for many years plant breeders have attempted to increase its concentration to improve the nutritional quality of these grains. The opaque2 mutation in maize doubles the lysine content in the endosperm, but the mechanism by which this occurs is unknown. We show that elongation factor 1 alpha (EF-1 alpha) is overexpressed in opaque2 endosperm compared with its normal counterpart and that there is a highly significant correlation between EF-1 alpha concentration and the total lysine content of the endosperm. This relationship is also true for two other cereals, sorghum and barley. It appears that genetic selection for genotypes with a high concentration of EF-1 alpha can significantly improve the nutritional quality of maize and other cereals.
The invention provides novel methods of using viral replicase polypeptides and polynucleotides. I... more The invention provides novel methods of using viral replicase polypeptides and polynucleotides. Included are methods for increasing transformation frequencies, increasing crop yield, providing a positive growth advantage, modulating cell division, transiently modulating cell division, and for providing a means of positive selection.
The endoreduplication cell cycle is a variant of the standard mitotic cell cycle in which reitera... more The endoreduplication cell cycle is a variant of the standard mitotic cell cycle in which reiterated rounds of DNA synthesis occur in the absence of chromosome segregation and cell division. The resulting polyploid cells are frequently found in plants and often occur in tissues with a high metabolic activity that accumulate storage molecules. In this chapter we review the current understanding of
Maize endosperm development is characterized by three distinct types of cell cycles: i) acytokine... more Maize endosperm development is characterized by three distinct types of cell cycles: i) acytokinetic mitosis during the coenocyte stage; ii) mitosis followed by cytokinesis during the mitotic stage; and iii) DNA replication without mitosis or cytokinesis during the endoreduplication stage. Although the molecular mechanisms controlling the transition between these different types of cell cycles are not fully understood, considerable progress is being made in the identification of key cell cycle regulators from model plant systems, and cereals in particular. This research is providing new insights into the importance of cell cycle regulation during the development of the maize endosperm. Traditional maize mutants with defective endosperms and the more recently available transposon-tagged mutants offer the opportunity to identify key regulators of cell division and endosperm development. In addition, transgenic approaches are being applied to unravel the relative contributions of cell ...
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