Expression of the ribulose-1,5-bisphosphate carboxylase large subunit gene and three small subunit genes in two cell types of maize leaves

Sheen, Jenq-Yunn; Bogorad, Lawrence

doi:10.1002/j.1460-2075.1986.tb04663.x

Cited by 81 publications

(50 citation statements)

References 44 publications

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“…The metabolic repression of photosynthetic genes apparently overrides other forms of regulation, e.g., light, tissue type, and developmental stage (Simpson et al, 1986;Kuhlemeier et al, 1987;Schell, 1987;Ha and An, 1988;Benfey and Chua, 1989;Ueda et al, 1989) because it is executed in young leaf cells under light. In this study, the young leaf cells (greening mesophyll protoplasts) were isolated from illuminated dark-grown seedlings, which is a well-established system for the study of the photosynthetic gene expression at an early developmental stage (Nelson et al, 1984;Sheen and Bogorad, 1986a, 1986bSimpson et al, 1986;Mosinger et al, 1988;Lam et al, 1989). The greening mesophyll protoplasts of maize provide an abundant and homogeneous cell population, synchronized in photosynthetic gene induction and expression, for the study of photosynthetic gene regulation.…”

Section: Discussionmentioning

confidence: 99%

Metabolic repression of transcription in higher plants.

1990

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Using freshly isolated maize mesophyll protoplasts and a transient expression method, I showed that the transcriptional activity of seven maize photosynthetic gene promoters is specifically and coordinately repressed by the photosynthetic end products sucrose and glucose and by the exogenous carbon source acetate. Analysis of deleted, mutated, and hybrid promoters showed that sugars and acetate inhibit the activity of distinct positive upstream regulatory elements without a common consensus. The metabolic repression of photosynthetic genes overrides other forms of regulation, e.g., light, tissue type, and developmental stage. Repression by sugars and repression by acetate are mediated by different mechanisms. The identification of conditions that avoid sugar repression overcomes a major obstacle to the study of photosynthetic gene regulation in higher plants.

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Section: Discussionmentioning

confidence: 99%

Metabolic repression of transcription in higher plants.

1990

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“…Upon illumination the transcripts increase 2-to 3-fold in abundance in BSC but become undetectable in MC (3)(4)(5). The maize nuclear gene rbcS-m3 (6) follows the general pattern of rbcS expression in maize, i.e., expression is induced in BSC and repressed in MC upon illumination of dark-grown seedlings.…”

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confidence: 95%

“…The large subunit is the product of a single chloroplast rbcL gene per chloroplast chromosome (1,2). The small subunits are encoded by a family of nuclear rbcS genes (3).…”

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confidence: 99%

TRM1, a YY1-like suppressor of rbcS-m3 expression in maize mesophyll cells

Purcell

Zucchi

et al. 2001

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

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The genes rbcS and rbcL encode, respectively, the small and large subunits of the photosynthetic carbon dioxide fixation enzyme ribulose bisphosphate carboxylase͞oxygenase. There is a single rbcL gene in each chloroplast chromosome; a family of rbcS genes is located in the nuclear genome. These two genes are not ex- L eaves of C3 plants contain a single type of photosynthetic cell. Each of these cells carries on all of the reactions of oxygenic photosynthesis and contains the carbon dioxide-fixing enzyme Rubisco (ribulose-1,5-bisphosphate carboxylase͞ oxygenase). This enzyme catalyzes the fixation of CO 2 to ribulose-1,5-phosphate and the production of two molecules of 3-phosphoglycerate.Maize is a C4 plant. Its leaves have two types of major photosynthetic cells: a cylinder of bundle sheath cells (BSC) surrounds each of the vascular bundles; mesophyll cells (MC) occupy the remainder of the space between the upper epidermis and the lower epidermis. Some MC and BSC are immediately adjacent to one another. In MC, CO 2 is fixed to phosphoenolpyruvate (PEP) by PEP carboxylase to form oxaloacetate, the latter, a four-carbon acid, is reduced to malate, which is transferred to BSC. CO 2 is released from the malate in BSC. Rubisco, which refixes the CO 2 , is present in BSC but not in MC. C4 species differ with regard to the exact product of oxaloactate that is moved from MC to BSC but in all cases Rubisco is found only in one cell type.Rubisco is comprised of eight large subunits, each of about 55 kDa, and eight small subunits, each of about 13 kDa. The large subunit is the product of a single chloroplast rbcL gene per chloroplast chromosome (1, 2). The small subunits are encoded by a family of nuclear rbcS genes (3).Transcripts of rbcS and rbcL are detectable in MC and BSC in leaves of dark-grown maize seedlings. Upon illumination the transcripts increase 2-to 3-fold in abundance in BSC but become undetectable in MC (3-5). The maize nuclear gene rbcS-m3 (6) follows the general pattern of rbcS expression in maize, i.e., expression is induced in BSC and repressed in MC upon illumination of dark-grown seedlings. About 35% of the total leaf rbcS mRNA in 24 h illuminated dark-grown maize is transcribed from rbcS-m3 (3). The control of repression of this gene in MC is the subject of the present work.Using an in situ reporter gene transient expression assay, we found previously that sequences of rbcS-m3 that lie between Ϫ93 bp and ϩ64 bp of the transcription start site are required for promoting photoregulated expression in BSC (7,8). On the other hand, photoregulated partial suppression of rbcS-m3-reporter gene expression in MC was found to require gene sequences that lie between Ϫ907 and Ϫ445 bp together with sequences that lie between ϩ720 bp and ϩ957 bp. The latter are just beyond the translation stop codon within the 3Ј transcribed region of the gene, but are equally effective when relocated 5Ј to the Ϫ907 to Ϫ445 corepressor-containing region. We also found that expression of the reporter gene is suppressed in MC only ...

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“…In plants with C4 photosynthesis, differentiation of cells with specialized photosynthetic functions is accompanied by increases in the abundance of chloroplast-encoded rbcL (Link et al, 1978) and psbA mRNAs (Sheen and Bogorad, 1986). Ir!…”

Section: Introductionmentioning

confidence: 99%