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A Network of Local and Redundant Gene Regulation Governs Arabidopsis Seed Maturation
"... have been edited and the authors have corrected proofs, but before the final, complete issue is published online. Early posting of articles reduces normal time to publication by several weeks. ..."
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have been edited and the authors have corrected proofs, but before the final, complete issue is published online. Early posting of articles reduces normal time to publication by several weeks.
RESEARCH ARTICLE LEAFY COTYLEDON1-LIKE Defines a Class of Regulators Essential for Embryo Development
"... Arabidopsis LEAFY COTYLEDON1 (LEC1) is a critical regulator required for normal development during the early and late phases of embryogenesis that is sufficient to induce embryonic development in vegetative cells. LEC1 encodes a HAP3 subunit of the CCAAT binding transcription factor. We show that th ..."
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Arabidopsis LEAFY COTYLEDON1 (LEC1) is a critical regulator required for normal development during the early and late phases of embryogenesis that is sufficient to induce embryonic development in vegetative cells. LEC1 encodes a HAP3 subunit of the CCAAT binding transcription factor. We show that the 10 Arabidopsis HAP3 (AHAP3) subunits can be divided into two classes based on sequence identity in their central, conserved B domain. LEC1 and its most closely related subunit, LEC1-LIKE (L1L), constitute LEC1-type AHAP3 subunits, whereas the remaining AHAP3 subunits are designated non-LEC1-type. Similar to LEC1, L1L is expressed primarily during seed development. However, suppression of L1L gene expression induced defects in embryo development that differed from those of lec1 mutants, suggesting that LEC1 and L1L play unique roles in embryogenesis. We show that L1L expressed under the control of DNA sequences flanking the LEC1 gene suppressed genetically the lec1 mutation, suggesting that the LEC1-type B domains of L1L and LEC1 are critical for their function in embryogenesis. Our results also suggest that LEC1-type HAP3 subunits arose from a common origin uniquely in plants. Thus, L1L, an essential regulator of embryo development, defines a unique class of plant HAP3 subunits.
A Network of Local and Redundant Gene Regulation Governs Arabidopsis Seed Maturation
"... [LEC1], and LEC2) control most aspects of seed maturation, such as accumulation of storage compounds, cotyledon identity, acquisition of desiccation tolerance, and dormancy. The molecular basis for complex genetic interactions among these regulators is poorly understood. By analyzing ABI3 and FUS3 e ..."
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[LEC1], and LEC2) control most aspects of seed maturation, such as accumulation of storage compounds, cotyledon identity, acquisition of desiccation tolerance, and dormancy. The molecular basis for complex genetic interactions among these regulators is poorly understood. By analyzing ABI3 and FUS3 expression in various single, double, and triple maturation mutants, we have identified multiple regulatory links among all four genes. We found that one of the major roles of LEC2 was to upregulate FUS3 and ABI3. The lec2 mutation is responsible for a dramatic decrease in ABI3 and FUS3 expression, and most lec2 phenotypes can be rescued by ABI3 or FUS3 constitutive expression. In addition, ABI3 and FUS3 positively regulate themselves and each other, thereby forming feedback loops essential for their sustained and uniform expression in the embryo. Finally, LEC1 also positively regulates ABI3 and FUS3 in the cotyledons. Most of the genetic controls discovered were found to be local and redundant, explaining why they had previously been overlooked. This works establishes a genetic framework for seed maturation, organizing the key regulators of this process into a hierarchical
1CHAPTER 1. GENE EXPRESSION PATTERNS DURING SOMATIC EMBRYO DEVELOPMENT AND GERMINATION IN MAIZE Hi II CALLUS CULTURES A paper submitted to Plant Molecular Biology
"... Gene expression patterns were proled during somatic embryogenesis in a regeneration-pro cient maize hybrid line, Hi II, in an eort to identify genes that might be used as developmental markers or targets to optimize regeneration steps for recovering maize plants from tissue culture. Gene expression ..."
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Gene expression patterns were proled during somatic embryogenesis in a regeneration-pro cient maize hybrid line, Hi II, in an eort to identify genes that might be used as developmental markers or targets to optimize regeneration steps for recovering maize plants from tissue culture. Gene expression proles were generated from embryogenic calli induced to undergo embryo maturation and germination. Over 1,000 genes in the 12,060 element arrays showed signicant time variation during somatic embryo develop-ment. A substantial number of genes were downregulated during embryo maturation, largely histone and ribosomal protein genes, which may result from a slowdown in cell proliferation and growth during embryo maturation. The expression of these genes dra-
Arabidopsis Seed Maturation Master Regulator FUS3 Revealed by Microarray Analysis
, 2010
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