A Dominant Negative Mutant of Cyclin-Dependent Kinase A Reduces Endoreduplication but Not Cell Size or Gene Expression in Maize Endosperm

Leiva-Neto, João T.; Grafi, Gideon; Sabelli, Paolo A.; Dante, Ricardo A.; Woo, Young‐Min; Maddock, S. E.; Gordon‐Kamm, William; Larkins, Brian A.

doi:10.1105/tpc.022178

Cited by 117 publications

(109 citation statements)

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“…This could reflect a difference in the level of specific CDKs, cell cycle activity, or a variety of other factors. Endosperm is mitotically active at 9 DAP, although endoreduplication has begun by this stage and one might expect an increase in S-phase-associated CDKs and a reduction in M-phase CDK activity (Grafi and Larkins, 1995;Leiva-Neto et al, 2004). In contrast to the inhibition of cyclin A1;3-containing CDK activity, there was essentially no effect of GST-Zeama;KRP;1 on the cyclin B1;3-associated CDK activity (Fig.…”

Section: Characterization Of Maize Krp Gene Expression During Endospementioning

confidence: 65%

“…Figure 8 shows the inhibition of histone H1 phosphorylation in the presence of the CKI and the accumulation of this activity in endosperm between 9 and 19 DAP. The results show that the inhibitory activity peaked between 15 and 19 DAP, coincident with the maximum stage of endoreduplication (Grafi and Larkins, 1995;Leiva-Neto et al, 2004).…”

Section: Zeama;krp;1 Does Not Account For All the Cdk Inhibitory Actimentioning

confidence: 83%

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Cyclin-Dependent Kinase Inhibitors in Maize Endosperm and Their Potential Role in Endoreduplication

et al. 2005

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Two maize (Zea mays) cyclin-dependent kinase (CDK) inhibitors, Zeama;KRP;1 and Zeama;KRP;2, were characterized and shown to be expressed in developing endosperm. Similar to the CDK inhibitors in Arabidopsis (Arabidopsis thaliana) and tobacco (Nicotiana tabacum), the maize proteins contain a carboxy-terminal region related to the inhibitory domain of the mammalian Cip/Kip inhibitors. Zeama;KRP;1 is present in the endosperm between 7 and 21 d after pollination, a period that encompasses the onset of endoreduplication, while the Zeama;KRP;2 protein declines during this time. Nevertheless, Zeama;KRP;1 accounts for only part of the CDK inhibitory activity that peaks coincident with the endoreduplication phase of endosperm development. In vitro assays showed that Zeama;KRP;1 and Zeama;KRP;2 are able to inhibit endosperm Cdc2-related CKD activity that associates with p13Suc1. They were also shown to specifically inhibit cyclin A1;3- and cyclin D5;1-associated CDK activities, but not cyclin B1;3/CDK. Overexpression of Zeama;KRP;1 in maize embryonic calli that ectopically expressed the wheat dwarf virus RepA protein, which counteracts retinoblastoma-related protein function, led to an additional round of DNA replication without nuclear division.

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Section: Characterization Of Maize Krp Gene Expression During Endospementioning

confidence: 65%

Section: Zeama;krp;1 Does Not Account For All the Cdk Inhibitory Actimentioning

confidence: 83%

Cyclin-Dependent Kinase Inhibitors in Maize Endosperm and Their Potential Role in Endoreduplication

et al. 2005

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“…Endosperm cell extracts were prepared according to procedures described in ref. 25. Nuclear and cytosolic fractions were obtained based on methods described in ref.…”

Section: Methodsmentioning

confidence: 99%

RBR3, a member of the retinoblastoma-related family from maize, is regulated by the RBR1/E2F pathway

Sabelli

Dante

Leiva-Neto

et al. 2005

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

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Retinoblastoma-related (RBR) proteins regulate cell division in higher eukaryotes by controlling the adenovirus E2 promoter binding factor (E2F)͞dimerization partner (DP) family of transcription factors that regulate expression of many genes involved in cell-cycle progression. We identified a previously undescribed member of the maize RBR family, RBR3, which has the characteristic structure and binding activities of pocket proteins, where interaction depends on a LxCxE motif in the partner proteins and a critical cysteine within the B pocket domain. Like other RBR proteins, RBR3 appears to be regulated by phosphorylation mediated by cyclindependent kinases. During endosperm development, RBR3 expression is restricted to the mitotic stage preceding the onset of endoreduplication. This finding suggests a role distinct from RBR1, which is constitutively expressed. Two sites in the RBR3 promoter bind to complexes containing maize E2F1 and DP proteins. Expression of wheat dwarf virus RepA protein, which blocks RBR1 activity and stimulates cell proliferation, dramatically up-regulates RBR3, but not RBR1, RNA in embryogenic maize calli. The results indicate that RBR3 expression is controlled by RBR1 through the activity of E2F͞DP and that RBR3 is the maize equivalent of mammalian p107. Furthermore, maize and related grasses might have evolved a compensatory mechanism among distinct types of RBR proteins to ensure robust control of pocket protein activity.cell cycle ͉ pocket protein ͉ RepA S pecific gene expression programs are key targets for cell-cycle control. As cells advance through G 1 and S phase, they sequentially up-regulate batteries of genes involved in licensing of replication origins, synthesis of G 1 ͞S-phase-specific cyclins (Cycs) and Cyc-dependent kinases (CDKs), and DNA synthesis. The adenovirus E2 promoter binding factor (E2F) family of transcription factors controls the expression of many genes required for entry into and execution of S-phase and cell-cycle progression (reviewed in refs. 1-4). Most E2F proteins require dimerization with a distantly related dimerization partner (DP) protein for activity. In humans, at least eight E2F family members have been identified that can be functionally grouped into transcriptional activators or repressors (reviewed in refs. 4 and 5), and a similar family of E2F proteins is present in plants (6-8).The retinoblastoma-related (RBR) family of proteins (RB, p107, and p130 in mammals) primarily represses the G 1 ͞S-phase transition of the cell cycle by inhibiting, directly (through masking of the E2F transactivation domain) or indirectly (by recruiting different chromatin-remodeling complexes and thereby silencing specific chromatin regions), the E2F͞DP family of transcription factors (reviewed in refs. 9 and 10). Collectively, the activity of RBR proteins results in inhibition of the expression of E2F-regulated genes in G 1 , effectively preventing the transition into S phase. The consensus understanding from many studies in mammals indicates that from late G 1 , in...

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“…Proteins from starchy endosperm samples or aleurone peels were extracted as described by Leiva-Neto et al (2004). Briefly, the samples were ground with a plastic pestle in NETN extraction buffer (20 mM TrisHCl, pH 8.0, 100 mM NaCl, 20 mM Na 2 EDTA, 0.5% Triton X-100, 5 mM NaF, 1 mM Na orthovanadate, freshly added 1 mM phenylmethylsulfonyl fluoride, and 1 mM DTT) and protease inhibitor cocktail (Sigma-Aldrich).…”

Section: Immunoblot Analysismentioning

confidence: 99%

Delivery of Prolamins to the Protein Storage Vacuole in Maize Aleurone Cells

et al. 2011

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Zeins, the prolamin storage proteins found in maize (Zea mays), accumulate in accretions called protein bodies inside the endoplasmic reticulum (ER) of starchy endosperm cells. We found that genes encoding zeins, a-globulin, and legumin-1 are transcribed not only in the starchy endosperm but also in aleurone cells. Unlike the starchy endosperm, aleurone cells accumulate these storage proteins inside protein storage vacuoles (PSVs) instead of the ER. Aleurone PSVs contain zeinrich protein inclusions, a matrix, and a large system of intravacuolar membranes. After being assembled in the ER, zeins are delivered to the aleurone PSVs in atypical prevacuolar compartments that seem to arise at least partially by autophagy and consist of multilayered membranes and engulfed cytoplasmic material. The zein-containing prevacuolar compartments are neither surrounded by a double membrane nor decorated by AUTOPHAGY RELATED8 protein, suggesting that they are not typical autophagosomes. The PSV matrix contains glycoproteins that are trafficked through a Golgi-multivesicular body (MVB) pathway. MVBs likely fuse with the multilayered, autophagic compartments before merging with the PSV. The presence of similar PSVs also containing prolamins and large systems of intravacuolar membranes in wheat (Triticum aestivum) and barley (Hordeum vulgare) starchy endosperm suggests that this trafficking mechanism may be common among cereals.The cereal endosperm consists of three main cell types: an inner mass of starchy endosperm cells, one to three layers of epidermal aleurone cells, and the transfer cells that contact the maternal vascular tissue (Olsen, 2004). The starchy endosperm accounts for 80 to 90% of the grain weight and contains large amounts of storage proteins and starch. These cells undergo programmed cell death during maturation. Aleurone cells are rich in protein storage vacuoles (PSVs), minerals, and lipid bodies and remain alive during seed development. It is assumed that the breakdown of proteins localized to PSVs in aleurone cells provides an essential source of the amino acids necessary for the synthesis of hydrolytic enzymes required for mobilizing food stored in the starchy endosperm (Filner and Varner, 1967;Jacobsen et al., 1988;Bethke et al., 1998).Besides its biological relevance as a model to study plant development, cell differentiation, and programmed cell death, the cereal endosperm is very important in terms of its nutritional value. Cereal grains contain less protein than do legume seeds, but because cereals are produced and consumed in much larger quantities, they are the main source of protein for the nutrition of humans and livestock (Shewry and Halford, 2002). The major storage proteins in maize (Zea mays) kernels are the alcoholsoluble prolamins, a type of storage proteins present only in grasses. Maize prolamins, referred to as zeins, are divided into different types: a-, b-, g-, and d-zeins (Coleman and Larkins, 1999) that differ in amino acid composition and structural properties (Shewry and Halford, 2002)...

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A Dominant Negative Mutant of Cyclin-Dependent Kinase A Reduces Endoreduplication but Not Cell Size or Gene Expression in Maize Endosperm

Cited by 117 publications

References 63 publications

Cyclin-Dependent Kinase Inhibitors in Maize Endosperm and Their Potential Role in Endoreduplication

Cyclin-Dependent Kinase Inhibitors in Maize Endosperm and Their Potential Role in Endoreduplication

RBR3, a member of the retinoblastoma-related family from maize, is regulated by the RBR1/E2F pathway

Delivery of Prolamins to the Protein Storage Vacuole in Maize Aleurone Cells

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