Leafy Cotyledon Mutants of Arabidopsis

Meinke, David W.; Franzmann, Linda H.; Nickle, Todd C.; Yeung, Edward C.

doi:10.2307/3869884

Cited by 192 publications

(176 citation statements)

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“…LEC1, which encodes subunit B9 of a nuclear factor Y protein (NF‐YB9), and the B3 domain protein LEC2 are part of a larger network of “LAFL” proteins (for L EC1/LEC1‐LIKE [L1L], A BSCISIC ACID [ABA] INSENSITIVE 3 [ABI3], F USCA3 [FUS3] and L EC2) that regulate embryo identity and maturation (Jia, McCarty, & Suzuki, 2013). Loss‐of‐function mutations in LAFL genes result in defects in cotyledon development, storage macromolecule accumulation, and desiccation tolerance in zygotic embryos (Keith, Kraml, Dengler, & McCourt, 1994; Meinke, Franzmann, Nickle, & Yeung, 1994; Parcy, Valon, Kohara, Misera, & Giraudat, 1997; Stone et al., 2001; West et al., 1994). In contrast, ectopic expression of LEC1 and LEC2 induces somatic embryo formation on the cotyledons and leaves of arabidopsis seedlings (Lotan et al., 1998; Stone et al., 2001).…”

Section: A Network Of Arabidopsis Transcription Factors Controls Somamentioning

confidence: 99%

A transcriptional view on somatic embryogenesis

2017

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Somatic embryogenesis is a form of induced plant cell totipotency where embryos develop from somatic or vegetative cells in the absence of fertilization. Somatic embryogenesis can be induced in vitro by exposing explants to stress or growth regulator treatments. Molecular genetics studies have also shown that ectopic expression of specific embryo‐ and meristem‐expressed transcription factors or loss of certain chromatin‐modifying proteins induces spontaneous somatic embryogenesis. We begin this review with a general description of the major developmental events that define plant somatic embryogenesis and then focus on the transcriptional regulation of this process in the model plant Arabidopsis thaliana (arabidopsis). We describe the different somatic embryogenesis systems developed for arabidopsis and discuss the roles of transcription factors and chromatin modifications in this process. We describe how these somatic embryogenesis factors are interconnected and how their pathways converge at the level of hormones. Furthermore, the similarities between the developmental pathways in hormone‐ and transcription‐factor‐induced tissue culture systems are reviewed in the light of our recent findings on the somatic embryo‐inducing transcription factor BABY BOOM.

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Section: A Network Of Arabidopsis Transcription Factors Controls Somamentioning

confidence: 99%

A transcriptional view on somatic embryogenesis

2017

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“…Lossof-function mutations in each gene cause defects in seed protein RNA accumulation, although to different degrees (12)(13)(14)(30)(31)(32)(33)(34)(35). Ectopic expression of each gene causes accumulation of seed protein RNAs in vegetative organs, although ABA is required or enhances seed protein RNA accumulation in plants overexpressing ABI3 and FUS3, respectively ( Fig.…”

Section: Lec2 Directly Activates Genes Involved In Maturation Processesmentioning

confidence: 99%

“…The LEC2 protein contains a DNA-binding B3 domain that is most closely related to that of FUS3 and ABI3 (10)(11)(12). The lec2 mutation causes localized defects in embryo filling, seed protein accumulation, and desiccation tolerance (12,13). LEC2 expression is normally limited primarily to seed development, although LEC2 RNA may be present at very low levels at other stages of the life cycle (12).…”

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Genes directly regulated by LEAFY COTYLEDON2 provide insight into the control of embryo maturation and somatic embryogenesis

Braybrook

Stone

Park

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

324

331

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The B3 domain protein LEAFY COTYLEDON2 (LEC2) is required for several aspects of embryogenesis, including the maturation phase, and is sufficient to induce somatic embryo development in vegetative cells. Here, we demonstrate that LEC2 directly controls a transcriptional program involved in the maturation phase of seed development. Induction of LEC2 activity in seedlings causes rapid accumulation of RNAs normally present primarily during the maturation phase. Several RNAs encode proteins with known roles in maturation processes, including seed-storage and lipid-body proteins. Clustering analyses identified other LEC2-induced RNAs not previously shown to be involved in the maturation phase. We show further that genes encoding these maturation RNAs all possess in their 5 flanking regions RY motifs, DNA elements bound by other closely related B3 domain transcription factors. Our finding that recombinant LEC2 specifically binds RY motifs from the 5 flanking regions of LEC2-induced genes provides strong evidence that these genes represent transcriptional targets of LEC2. Although these LEC2-induced RNAs accumulate primarily during the maturation phase, we show that a subset, including AGL15 and IAA30, accumulate in seeds containing zygotes. We discuss how identification of LEC2 target genes provides a potential link between the roles of LEC2 in the maturation phase and in the induction of somatic embryogenesis.Arabidopsis ͉ B3 domain E mbryogenesis in higher plants can be divided conceptually into two distinct phases. Early in embryogenesis, during the morphogenesis phase, the basic body plan of the plant is established with regional specification of apical-basal and radial domains from which morphological structures derive, fixation of polarity from specification of the shoot-root axis, and formation of embryonic tissue and organ systems (1-3). The morphogenesis phase is followed temporally by the maturation phase, although the two phases can overlap (4, 5). During the maturation phase, embryo cell-division rates decline markedly, embryo cells acquire the ability to withstand desiccation, and embryo cell growth occurs, with the accumulation of storage reserves that comprise lipids and proteins in Arabidopsis (6, 7). At the end of the maturation phase, the embryo becomes quiescent metabolically as the seed desiccates.The maturation phase can be viewed as an interruption of an ancestral life cycle, as occurs in lower plants, in which there are no periods of maturation or dormancy separating the end of embryogenesis and the beginning of postembryonic development (4). Evolution of this unique mode of embryogenesis has enabled higher plants to make seeds. The ability to make seeds has provided tremendous selective advantages that, in part, account for the success of the angiosperms (8, 9). Little is known at a mechanistic level about the processes by which the maturation phase has been integrated into the higher plant life cycle. LEAFY COTYLEDON2 (LEC2), along with ABA INSEN-SITIVE3 (ABI3), and FUSCA3 (FUS3), have been im...

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“…: 919-962-2098; Fax: 919-962-6840; E-mail: rsq@unc.edu. 1 The abbreviations used are: ABA, abscisic acid; bp, base pair(s);tion require factors other than ABA (18), as well as regulatory loci whose control extends beyond ABA response pathways (19). Since the Em gene appears to be exclusively expressed in embryos and requires both ABA and the seed-specific regulatory protein VP1, we have focused our studies toward understanding how VP1 interacts with the transcriptional controlling components of the Em gene.…”

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confidence: 99%

A Conserved Domain of the viviparous-1 Gene Product Enhances the DNA Binding Activity of the bZIP Protein EmBP-1 and Other Transcription Factors

Hill¹,

Nantel²,

Rock³

et al. 1996

Journal of Biological Chemistry

106

115

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The maize VP1 protein is a seed-specific regulator of gene expression that effects the expression of a subset of abscisic acid (ABA)-regulated genes that are expressed during the maturation program of the seed. In addition, VP1 has pleiotropic effects on seed development that are not related to ABA. In transient expression assays, VP1 has been shown to transactivate gene expression through at least two distinct promoter elements: the G boxes from the ABA-inducible wheat Em gene and the SphI box from the maize C1 gene. We have investigated how VP1 can transactivate gene expression through diverse promoter elements by analyzing its association in vitro with EmBP-1, a factor that binds the Em promoter. We demonstrate that VP1 can greatly enhance the DNA binding activity of EmBP-1 in a gel retardation assay. This enhancing activity has also been observed on transcription factors as diverse as Opaque-2, Max, Sp1, and NF-B. Deletion of a small but highly conserved region (BR2) in VP1 eliminates the enhancement in vitro as well as the ability of VP1 to transactivate Em gene expression in a transient expression assay. A 40-amino acid fragment from VP1 sandwiched between the maltose-binding protein and LacZ can confer the enhancement function to this fusion protein in vitro. A weak and relatively nonspecific interaction between BR2 and DNA is demonstrated by UV cross-linking. The in vitro properties we observe for VP1 might explain the regulatory effects of VP1 on a diverse set of genes and why mutations in the vp1 locus have pleiotropic effects.

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Leafy Cotyledon Mutants of Arabidopsis

Cited by 192 publications

References 13 publications

A transcriptional view on somatic embryogenesis

A transcriptional view on somatic embryogenesis

Genes directly regulated by LEAFY COTYLEDON2 provide insight into the control of embryo maturation and somatic embryogenesis

A Conserved Domain of the viviparous-1 Gene Product Enhances the DNA Binding Activity of the bZIP Protein EmBP-1 and Other Transcription Factors

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