Sunflower root growth regulation: the role of jasmonic acid and its relation with auxins

Sirtuins (SIRTs) are NAD+-dependent deacetylases that regulate proliferation and cell death. In the human ovary, granulosa cells express sirtuin 1 (SIRT1), which has also been detected in human tumors derived from granulosa cells, i.e., granulosa cell tumors (GCTs), and in KGN cells. KGN cells are an established cellular model for the majority of GCTs and were used to explore the role of SIRT1. The SIRT1 activator SRT2104 increased cell proliferation. By contrast, the inhibitor EX527 reduced cell numbers, without inducing apoptosis. These results were supported by the outcome of siRNA-mediated silencing studies. A tissue microarray containing 92 GCTs revealed nuclear and/or cytoplasmic SIRT1 staining in the majority of the samples, and also, SIRT2-7 were detected in most samples. The expression of SIRT1–7 was not correlated with the survival of the patients; however, SIRT3 and SIRT7 expression was significantly correlated with the proliferation marker Ki-67, implying roles in tumor cell proliferation. SIRT3 was identified by a proteomic analysis as the most abundant SIRT in KGN. The results of the siRNA-silencing experiments indicate involvement of SIRT3 in proliferation. Thus, several SIRTs are expressed by GCTs, and SIRT1 and SIRT3 are involved in the growth regulation of KGN. If transferable to GCTs, these SIRTs may represent novel drug targets.

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The Arabidopsis Root Tip (Phospho)Proteomes at Growth-Promoting versus Growth-Repressing Conditions Reveal Novel Root Growth Regulators

Cells ◽

10.3390/cells10071665 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1665

Author(s):

Natalia Nikonorova ◽

Evan Murphy ◽

Cassio Flavio Fonseca de Lima ◽

Shanshuo Zhu ◽

Brigitte van de Cotte ◽

...

Keyword(s):

Cell Wall ◽

Root Growth ◽

Growth Regulators ◽

Growth Regulation ◽

Phosphorylation Site ◽

Primary Root ◽

Root Tip ◽

Arabidopsis Root ◽

Growth Promoting ◽

The Impact

Auxin plays a dual role in growth regulation and, depending on the tissue and concentration of the hormone, it can either promote or inhibit division and expansion processes in plants. Recent studies have revealed that, beyond transcriptional reprogramming, alternative auxin-controlled mechanisms regulate root growth. Here, we explored the impact of different concentrations of the synthetic auxin NAA that establish growth-promoting and -repressing conditions on the root tip proteome and phosphoproteome, generating a unique resource. From the phosphoproteome data, we pinpointed (novel) growth regulators, such as the RALF34-THE1 module. Our results, together with previously published studies, suggest that auxin, H+-ATPases, cell wall modifications and cell wall sensing receptor-like kinases are tightly embedded in a pathway regulating cell elongation. Furthermore, our study assigned a novel role to MKK2 as a regulator of primary root growth and a (potential) regulator of auxin biosynthesis and signalling, and suggests the importance of the MKK2 Thr31 phosphorylation site for growth regulation in the Arabidopsis root tip.

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Role of jasmonic acid in plants: the molecular point of view

Plant Cell Reports ◽

10.1007/s00299-021-02687-4 ◽

2021 ◽

Author(s):

Mouna Ghorbel ◽

Faiçal Brini ◽

Anket Sharma ◽

Marco Landi

Keyword(s):

Jasmonic Acid ◽

Point Of View

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Lymphoma models for B cell activation and tolerance. X. Anti-mu-mediated growth arrest and apoptosis of murine B cell lymphomas is prevented by the stabilization of myc.

Journal of Experimental Medicine ◽

10.1084/jem.179.1.221 ◽

1994 ◽

Vol 179 (1) ◽

pp. 221-228 ◽

Cited By ~ 68

Author(s):

G Fischer ◽

S C Kent ◽

L Joseph ◽

D R Green ◽

D W Scott

Keyword(s):

Growth Inhibition ◽

B Cell ◽

Antisense Oligonucleotides ◽

Growth Regulation ◽

Cell Activation ◽

Transforming Growth Factor ◽

B Cell Activation ◽

Tgf Beta ◽

B Cell Lymphomas

Treatment of the WEHI-2131 or CH31 B cell lymphomas with anti-mu or transforming growth factor (TGF)-beta leads to growth inhibition and subsequent cell death via apoptosis. Since anti-mu stimulates a transient increase in c-myc and c-fos transcription in these lymphomas, we examined the role of these proteins in growth regulation using antisense oligonucleotides. Herein, we demonstrate that antisense oligonucleotides for c-myc prevent both anti-mu- and TGF-beta-mediated growth inhibition in the CH31 and WEHI-231 B cell lymphomas, whereas antisense c-fos has no effect. Furthermore, antisense c-myc promotes the appearance of phosphorylated retinoblastoma protein in the presence of anti-mu and prevents the progression to apoptosis as measured by propidium iodide staining. Northern and Western analyses show that c-myc message and the levels of multiple myc proteins were maintained in the presence of antisense c-myc, results indicating that myc species are critical for the continuation of proliferation and the prevention of apoptosis. These data implicate c-myc in the negative signaling pathway of both TGF-beta and anti-mu.

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Corrigendum: Physiological and Proteomic Analysis of the Rice Mutant cpm2 Suggests a Negative Regulatory Role of Jasmonic Acid in Drought Tolerance

Frontiers in Plant Science ◽

10.3389/fpls.2018.00465 ◽

2018 ◽

Vol 9 ◽

Author(s):

Rohit Dhakarey ◽

Manish L. Raorane ◽

Achim Treumann ◽

Preshobha K. Peethambaran ◽

Rachel R. Schendel ◽

...

Keyword(s):

Drought Tolerance ◽

Jasmonic Acid ◽

Proteomic Analysis ◽

Regulatory Role ◽

Rice Mutant ◽

Negative Regulatory Role

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Restoration of Defective Cross Talk in ssi2 Mutants: Role of Salicylic Acid, Jasmonic Acid, and Fatty Acids in SSI2-Mediated Signaling

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2003.16.11.1022 ◽

2003 ◽

Vol 16 (11) ◽

pp. 1022-1029 ◽

Cited By ~ 42

Author(s):

Pradeep Kachroo ◽

Aardra Kachroo ◽

Ludmila Lapchyk ◽

David Hildebrand ◽

Daniel F. Klessig

Keyword(s):

Cell Death ◽

Salicylic Acid ◽

Jasmonic Acid ◽

Cross Talk ◽

Pr Genes ◽

Exogenous Application ◽

Basal Level Expression ◽

Sa Signaling ◽

Spontaneous Cell Death

The Arabidopsis mutants ssi2 and fab2 are defective in stearoyl ACP desaturase, which causes altered salicylic acid (SA)- and jasmonic acid (JA)-mediated defense signaling. Both ssi2 and fab2 plants show spontaneous cell death, express PR genes constitutively, accumulate high levels of SA, and exhibit enhanced resistance to bacterial and oomycete pathogens. In contrast to constitutive activation of the SA pathway, ssi2 and fab2 plants are repressed in JA-mediated induction of the PDF1.2 gene, which suggests that the SSI2-mediated signaling pathway modulates cross talk between the SA and JA pathways. In this study, we have characterized two recessive nonallelic mutants in the ssi2 background, designated as rdc (restorer of defective cross talk) 2 and rdc8. Both ssi2 rdc mutants are suppressed in constitutive SA signaling, show basal level expression of PR-1 gene, and induce high levels of PDF1.2 in response to exogenous application of JA. Interestingly, while the rdc8 mutation completely abolishes spontaneous cell death in ssi2 rdc8 plants, the ssi2 rdc2 plants continue to show some albeit reduced cell death. Fatty acid (FA) analysis showed a reduction in 16:3 levels in ssi2 rdc8 plants, which suggests that this mutation may limit the flux of FAs into the pro-karyotic pathway of glycerolipid biosynthesis. Both rdc2 and rdc8 continue to accumulate high levels of 18:0, which suggests that 18:0 levels were responsible for neither constitutive SA signaling nor repression of JA-induced expression of the PDF1.2 gene in ssi2 plants. We also analyzed SA and JA responses of the fab2-derived shs1 mutant, which accumulates levels of 18:0 over 50% lower than those in the fab2 plants. Even though fab2 shs1 plants were morphologically bigger than fab2 plants, they expressed PR genes constitutively, showed HR-like cell death, and accumulated elevated levels of SA. However, unlike the ssi2 rdc plants, fab2 shs1 plants were unable to induce high levels of PDF1.2 expression in response to exogenous application of JA. Together, these results show that defective cross talk in ssi2 can be restored by second site mutations and is independent of morphological size of the plants, cell death, and elevated levels of 18:0.

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