The Seed-Specific Transcription Factor VP1 (OSVP1) Is Expressed in Rice Suspension-Cultured Cells

Nakagawa, Hitoshi; Ohkura, Eiko; Ohmiya, Kunio; Hattori, Tsukaho

doi:10.1093/oxfordjournals.pcp.a028953

Cited by 17 publications

(10 citation statements)

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“…Vp1 is expressed in rice suspension-cultured cells (Nakagawa et al, 1996) and ABI3 is expressed in meristematic tissues of Arabidopsis and poplar (Populus spp. ), under conditions of growth arrest (Rohde et al, 1999(Rohde et al, , 2002.…”

Section: Discussionmentioning

confidence: 99%

Abscisic Acid and Stress Signals InduceViviparous1Expression in Seed and Vegetative Tissues of Maize

et al. 2007

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Viviparous1 (Vp1) encodes a B3 domain-containing transcription factor that is a key regulator of seed maturation in maize (Zea mays). However, the mechanisms of Vp1 regulation are not well understood. To examine physiological factors that may regulate Vp1 expression, transcript levels were monitored in maturing embryos placed in culture under different conditions. Expression of Vp1 decreased after culture in hormone-free medium, but was induced by salinity or osmotic stress. Application of exogenous abscisic acid (ABA) also induced transcript levels within 1 h in a dose-dependent manner. The Vp1 promoter fused to b-glucuronidase or green fluorescent protein reproduced the endogenous Vp1 expression patterns in transgenic maize plants and also revealed previously unknown expression domains of Vp1. The Vp1 promoter is active in the embryo and aleurone cells of developing seeds and, upon drought stress, was also found in phloem cells of vegetative tissues, including cobs, leaves, and stems. Sequence analysis of the Vp1 promoter identified a potential ABA-responsive complex, consisting of an ACGT-containing ABA response element (ABRE) and a coupling element 1-like motif. Electrophoretic mobility shift assay confirmed that the ABRE and putative coupling element 1 components specifically bound proteins in embryo nuclear protein extracts. Treatment of embryos in hormone-free Murashige and Skoog medium blocked the ABRE-protein interaction, whereas exogenous ABA or mannitol treatment restored this interaction. Our data support a model for a VP1-dependent positive feedback mechanism regulating Vp1 expression during seed maturation.

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Section: Discussionmentioning

confidence: 99%

Abscisic Acid and Stress Signals InduceViviparous1Expression in Seed and Vegetative Tissues of Maize

et al. 2007

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“…However, the results of transient co‐transfection assays should be interpreted with caution. The ABA‐response of the rice cell‐line used for the protoplast transient assay could be similar to those of embryos because OSVP1 is expressed at an equal or higher level (Nakagawa et al . 1996a).…”

Section: Discussionmentioning

confidence: 99%

ACGT‐containing abscisic acid response element (ABRE) and coupling element 3 (CE3) are functionally equivalent

et al. 1999

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SummaryACGT-containing ABA response elements (ABREs) have been functionally identi®ed in the promoters of various genes. In addition, single copies of ABRE have been found to require a cis-acting, coupling element to achieve ABA induction. A coupling element 3 (CE3) sequence, originally identi®ed as such in the barley HVA1 promoter, is found approximately 30 bp downstream of motif A (ACGT-containing ABRE) in the promoter of the Osem gene. The relationship between these two elements was further de®ned by linker-scan analyses of a 55 bp fragment of the Osem promoter, which is suf®cient for ABA-responsiveness and VP1 activation. The analyses revealed that both motif A and CE3 sequence were required not only for ABAresponsiveness but also for VP1 activation. Since the sequences of motif A and CE3 were found to be similar, motif-exchange experiments were carried out. The experiments demonstrated that motif A and CE3 were interchangeable by each other with respect to both ABA and VP1 regulation. In addition, both sequences were shown to be recognized by a VP1-interacting, ABAresponsive bZIP factor TRAB1. These results indicate that ACGT-containing ABREs and CE3 are functionally equivalent cis-acting elements. Furthermore, TRAB1 was shown to bind two other non-ACGT ABREs. Based on these results, all these ABREs including CE3 are proposed to be categorized into a single class of cisacting elements.

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“…Our results showing that the distB tetramer does not respond to ABA in the absence of ABI3 are in contrast with results by others ( Ono et al ., 1996 ; Skriver et al ., 1991 ; Vasil et al ., 1995 ), showing that tetramers of Em1a‐type ABREs are responsive to ABA independently of ABI3. However, the type of cell lines used in those studies express Vp1 ( Hollung et al ., 1997 ; Nakagawa et al ., 1996 ), and thus it is probable that the reported ABI3‐independent ABA responses actually reflect endogenous VP1 activity. Another Em1a‐type ABRE displaying ABI3‐independent response to ABA is Hex3 ( Table 1).…”

Section: Discussionmentioning

confidence: 99%

Transactivation of the Brassica napus napin promoter by ABI3 requires interaction of the conserved B2 and B3 domains of ABI3 with different cis‐elements: B2 mediates activation through an ABRE, whereas B3 interacts with an RY/G‐box

et al. 2000

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SummaryThe transcriptional activator ABI3 is a key regulator of gene expression during embryo maturation in crucifers. In monocots, the related VP1 protein regulates the Em promoter synergistically with abscisic acid (ABA). We identi®ed cis-elements in the Brassica napus napin napA promoter mediating regulation by ABI3 and ABA, by analyzing substitution mutation constructs of napA in transgenic tobacco plantlets ectopically expressing ABI3. In transient analysis using particle bombardment of tobacco leaf sections, a tetramer of the distB ABRE (abscisic acid-responsive element) mediated transactivation by ABI3 and ABI3-dependent response to ABA, whereas a tetramer of the composite RY/G complex, containing RY repeats and a G-box, mediated only ABA-independent transactivation by ABI3. Deletion of the conserved B2 and B3 domains of ABI3 abolished transactivation of napA by ABI3. The two domains of ABI3 interact with different cis-elements: B2 is necessary for ABA-independent and ABA-dependent activations through the distB ABRE, whereas B3 interacts with the RY/G complex. Thus B2 mediates the interaction of ABI3 with the protein complex at the ABRE. The regulation of napA by ABI3 differs from Em regulation by VP1, in that the B3 domain of ABI3 is essential for the ABA-dependent regulation of napA.

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The Seed-Specific Transcription Factor VP1 (OSVP1) Is Expressed in Rice Suspension-Cultured Cells

Cited by 17 publications

References 0 publications

Abscisic Acid and Stress Signals InduceViviparous1Expression in Seed and Vegetative Tissues of Maize

Abscisic Acid and Stress Signals InduceViviparous1Expression in Seed and Vegetative Tissues of Maize

ACGT‐containing abscisic acid response element (ABRE) and coupling element 3 (CE3) are functionally equivalent

Transactivation of the Brassica napus napin promoter by ABI3 requires interaction of the conserved B2 and B3 domains of ABI3 with different cis‐elements: B2 mediates activation through an ABRE, whereas B3 interacts with an RY/G‐box

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