scholarly journals A cis-carotene derived apocarotenoid regulates etioplast and chloroplast development

2019 ◽  
Author(s):  
Christopher I Cazzonelli ◽  
Xin Hou ◽  
Yagiz Alagoz ◽  
John Rivers ◽  
Namraj Dhami ◽  
...  
Keyword(s):  
Chloroplast Development ◽  
Carotenoid Biosynthesis ◽  
Forward Genetics ◽  
Regulatory Function ◽  
Prolamellar Body ◽  
Carotenoid Cleavage Dioxygenase ◽  
Protochlorophyllide Oxidoreductase ◽  
Plastid Development ◽  
Dark Light ◽  
Protein Levels

ABSTRACTCarotenoids are core plastid components, yet a regulatory function during plastid biogenesis remains enigmatic. A unique carotenoid biosynthesis mutant, carotenoid chloroplast regulation 2 (ccr2), that has no prolamellar body (PLB) and normal PROTOCHLOROPHYLLIDE OXIDOREDUCTASE (POR) levels, was used to demonstrate a regulatory function for carotenoids under varied dark-light regimes. A forward genetics approach revealed how an epistatic interaction between a (-carotene isomerase mutant (ziso-155) and ccr2 blocked the biosynthesis of specific cis-carotenes and restored PLB formation in etioplasts. We attributed this to a novel apocarotenoid signal, as chemical inhibition of carotenoid cleavage dioxygenase activity restored PLB formation in ccr2 etioplasts during skotomorphogenesis. The apocarotenoid acted in parallel to the transcriptional repressor of photomorphogenesis, DEETIOLATED1 (DET1), to post-transcriptionally regulate PROTOCHLOROPHYLLIDE OXIDOREDUCTASE (POR), PHYTOCHROME INTERACTING FACTOR3 (PIF3) and ELONGATED HYPOCOTYL5 (HY5) protein levels. The apocarotenoid signal and det1 complemented each other to restore POR levels and PLB formation, thereby controlling plastid development.One-sentence summaryCarotenoids are not just required as core components for plastid biogenesis, they can be cleaved into an apocarotenoid signal that regulates etioplast and chloroplast development during extended periods of darkness.

scholarly journals A cis-carotene derived apocarotenoid regulates etioplast and chloroplast development

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Christopher I Cazzonelli ◽  
Xin Hou ◽  
Yagiz Alagoz ◽  
John Rivers ◽  
Namraj Dhami ◽  
...  
Keyword(s):  
Carotenoid Biosynthesis ◽  
Forward Genetics ◽  
Regulatory Function ◽  
Prolamellar Body ◽  
Carotenoid Cleavage Dioxygenase ◽  
Protochlorophyllide Oxidoreductase ◽  
Plastid Development ◽  
Dark Light ◽  
Light Regimes ◽  
Protein Levels

Carotenoids are a core plastid component and yet their regulatory function during plastid biogenesis remains enigmatic. A unique carotenoid biosynthesis mutant, carotenoid chloroplast regulation 2 (ccr2), that has no prolamellar body (PLB) and normal PROTOCHLOROPHYLLIDE OXIDOREDUCTASE (POR) levels, was used to demonstrate a regulatory function for carotenoids and their derivatives under varied dark-light regimes. A forward genetics approach revealed how an epistatic interaction between a ζ-carotene isomerase mutant (ziso-155) and ccr2 blocked the biosynthesis of specific cis-carotenes and restored PLB formation in etioplasts. We attributed this to a novel apocarotenoid retrograde signal, as chemical inhibition of carotenoid cleavage dioxygenase activity restored PLB formation in ccr2 etioplasts during skotomorphogenesis. The apocarotenoid acted in parallel to the repressor of photomorphogenesis, DEETIOLATED1 (DET1), to transcriptionally regulate PROTOCHLOROPHYLLIDE OXIDOREDUCTASE (POR), PHYTOCHROME INTERACTING FACTOR3 (PIF3) and ELONGATED HYPOCOTYL5 (HY5). The unknown apocarotenoid signal restored POR protein levels and PLB formation in det1, thereby controlling plastid development.

scholarly journals Carotenoid Biosynthesis and Plastid Development in Plants: The Role of Light

2021 ◽  
Vol 22 (3) ◽  
pp. 1184
Author(s):  
Rocio Quian-Ulloa ◽  
Claudia Stange
Keyword(s):  
Light Quality ◽  
Chloroplast Development ◽  
Chlorophyll Biosynthesis ◽  
Carotenoid Biosynthesis ◽  
Plastid Development ◽  
Carotenoid Synthesis ◽  
Role Of Light ◽  
Synthesis Regulation ◽  
Effect Of Light

Light is an important cue that stimulates both plastid development and biosynthesis of carotenoids in plants. During photomorphogenesis or de-etiolation, photoreceptors are activated and molecular factors for carotenoid and chlorophyll biosynthesis are induced thereof. In fruits, light is absorbed by chloroplasts in the early stages of ripening, which allows a gradual synthesis of carotenoids in the peel and pulp with the onset of chromoplasts’ development. In roots, only a fraction of light reaches this tissue, which is not required for carotenoid synthesis, but it is essential for root development. When exposed to light, roots start greening due to chloroplast development. However, the colored taproot of carrot grown underground presents a high carotenoid accumulation together with chromoplast development, similar to citrus fruits during ripening. Interestingly, total carotenoid levels decrease in carrots roots when illuminated and develop chloroplasts, similar to normal roots exposed to light. The recent findings of the effect of light quality upon the induction of molecular factors involved in carotenoid synthesis in leaves, fruit, and roots are discussed, aiming to propose consensus mechanisms in order to contribute to the understanding of carotenoid synthesis regulation by light in plants.

scholarly journals A PPR Protein ACM1 Is Involved in Chloroplast Gene Expression and Early Plastid Development in Arabidopsis

2021 ◽  
Vol 22 (5) ◽  
pp. 2512
Author(s):  
Xinwei Wang ◽  
Yaqi An ◽  
Ye Li ◽  
Jianwei Xiao
Keyword(s):  
Fluorescent Protein ◽  
Chloroplast Development ◽  
Nuclear Gene ◽  
Pentatricopeptide Repeat ◽  
Plastid Development ◽  
Chloroplast Gene Expression ◽  
Knock Out ◽  
Rnai Line ◽  
Ppr Protein ◽  
P Type

Chloroplasts cannot develop normally without the coordinated action of various proteins and signaling connections between the nucleus and the chloroplast genome. Many questions regarding these processes remain unanswered. Here, we report a novel P-type pentatricopeptide repeat (PPR) factor, named Albino Cotyledon Mutant1 (ACM1), which is encoded by a nuclear gene and involved in chloroplast development. Knock-down of ACM1 transgenic plants displayed albino cotyledons but normal true leaves, while knock-out of the ACM1 gene in seedlings was lethal. Fluorescent protein analysis showed that ACM1 was specifically localized within chloroplasts. PEP-dependent plastid transcript levels and splicing efficiency of several group II introns were seriously affected in cotyledons in the RNAi line. Furthermore, denaturing gel electrophoresis and Western blot experiments showed that the accumulation of chloroplast ribosomes was probably damaged. Collectively, our results indicate ACM1 is indispensable in early chloroplast development in Arabidopsis cotyledons.

scholarly journals Knockdown of Long Non-Coding RNA XIST Inhibited Doxorubicin Resistance in Colorectal Cancer by Upregulation of miR-124 and Downregulation of SGK1

2018 ◽  
Vol 51 (1) ◽  
pp. 113-128 ◽  
Author(s):  
Jia Zhu ◽  
Rui Zhang ◽  
Dongxiang Yang ◽  
Jibin Li ◽  
Xiaofei Yan ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Western Blot ◽  
Molecular Mechanisms ◽  
Luciferase Reporter ◽  
Regulatory Function ◽  
Glutathione S Transferase ◽  
Protein Levels ◽  
Qrt Pcr ◽  
Ic50 Value

Background/Aims: Doxorubicin (DOX) is a widely used chemotherapeutic agent for colorectal cancer (CRC). However, the acquirement of DOX resistance limits its clinical application for cancer therapy. Mounting evidence has suggested that aberrantly expressed lncRNAs contribute to drug resistance of various tumors. Our study aimed to explore the role and molecular mechanisms of lncRNA X-inactive specific transcript (XIST) in chemoresistance of CRC to DOX. Methods: The expressions of XIST, miR-124, serum and glucocorticoid-inducible kinase 1 (SGK1) mRNA in DOX-resistant CRC tissues and cells were detected by qRT-PCR or western blot analysis. DOX sensitivity was assessed by detecting IC50 value of DOX, the protein levels of P-glycoprotein (P-gp) and glutathione S-transferase-π (GST-π) and apoptosis. The interactions between XIST, miR-124 and SGK1 were confirmed by luciferase reporter assay, qRT-PCR and western blot. Xenograft tumor assay was used to verify the role of XIST in DOX resistance in CRC in vivo. Results: XIST expression was upregulated and miR-124 expression was downregulated in DOX-resistant CRC tissues and cells. Knockdown of XIST inhibited DOX resistance of CRC cells, as evidenced by the reduced IC50 value of DOX, decreased P-gp and GST-π levels and enhanced apoptosis in XIST-silenced DOX-resistant CRC cells. Additionally, XIST positively regulated SGK1 expression by interacting with miR-124 in DOX-resistant CRC cells. miR-124 suppression strikingly reversed XIST-knockdown-mediated repression on DOX resistance in DOX-resistant CRC cells. Moreover, SGK1-depletion-elicited decrease of DOX resistance was greatly restored by XIST overexpression or miR-124 inhibition in DOX-resistant CRC cells. Furthermore, XIST knockdown enhanced the anti-tumor effect of DOX in CRC in vivo. Conclusion: XIST exerted regulatory function in resistance of DOX possibly through miR-124/SGK1 axis, shedding new light on developing promising therapeutic strategy to overcome chemoresistance in CRC patients.

Somatic instability of carotenoid biosynthesis in the tomato ghost mutant and its effect on plastid development

Planta ◽  
1987 ◽  
Vol 171 (1) ◽  
pp. 11-18 ◽  
Author(s):  
P. A. Scolnik ◽  
P. Hinton ◽  
I. M. Greenblatt ◽  
G. Giuliano ◽  
M. R. Delanoy ◽  
...  
Keyword(s):  
Carotenoid Biosynthesis ◽  
Plastid Development ◽  
Somatic Instability

scholarly journals Microscopic Analyses of Fruit Cell Plastid Development in Loquat (Eriobotrya japonica) during Fruit Ripening

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 448 ◽  
Author(s):  
Pengjun Lu ◽  
Ruqian Wang ◽  
Changqing Zhu ◽  
Xiumin Fu ◽  
Shasha Wang ◽  
...  
Keyword(s):  
Fruit Ripening ◽  
De Novo ◽  
Microscopic Analysis ◽  
Carotenoid Biosynthesis ◽  
Direct Conversion ◽  
Eriobotrya Japonica ◽  
Plastid Development ◽  
Carotenoid Accumulation ◽  
The Relationship ◽  
Late Stages

Plastids are sites for carotenoid biosynthesis and accumulation, but detailed information on fruit plastid development and its relation to carotenoid accumulation remains largely unclear. Here, using Baisha (BS; white-fleshed) and Luoyangqing (LYQ; red-fleshed) loquat (Eriobotrya japonica), a detailed microscopic analysis of plastid development during fruit ripening was carried out. In peel cells, chloroplasts turned into smaller chromoplasts in both cultivars, and the quantity of plastids in LYQ increased by one-half during fruit ripening. The average number of chromoplasts per peel cell in fully ripe fruit was similar between the two cultivars, but LYQ peel cell plastids were 20% larger and had a higher colour density, associated with the presence of larger plastoglobules. In flesh cells, chromoplasts could be observed only in LYQ during the middle and late stages of ripening, and the quantity on a per-cell basis was higher than that in peel cells, but the size of chromoplasts was smaller. It was concluded that chromoplasts are derived from the direct conversion of chloroplasts to chromoplasts in the peel, and from de novo differentiation of proplastids into chromoplasts in flesh. The relationship between plastid development and carotenoid accumulation is discussed.

Developmental expression of Sp1 in the mouse

1991 ◽  
Vol 11 (4) ◽  
pp. 2189-2199
Author(s):  
J D Saffer ◽  
S P Jackson ◽  
M B Annarella
Keyword(s):  
Housekeeping Genes ◽  
Cell Types ◽  
Immunohistochemical Localization ◽  
Developmental Expression ◽  
Regulatory Function ◽  
General Role ◽  
Protein Levels ◽  
Rna Analysis ◽  
Different Cell Types ◽  
Unexpected Difference

The expression of the trans-acting transcription factor Sp1 in mice was defined by a combination of RNA analysis and immunohistochemical localization of the Sp1 protein. Although ubiquitously expressed, there was an unexpected difference of at least 100-fold in the amount of Sp1 message in different cell types. Sp1 protein levels showed corresponding marked differences. Substantial variations in Sp1 expression were also found in some cell types at different stages of development. Sp1 levels appeared to be highest in developing hematopoietic cells, fetal cells, and spermatids, suggesting that an elevated Sp1 level is associated with the differentiation process. These results indicate that Sp1 has a regulatory function in addition to its general role in the transcription of housekeeping genes.

Notizen: Changes in the Iron and Phosphorus Content of Stroma Inclusions during Etioplast-Chloroplast Development in Nicotiana

1977 ◽  
Vol 32 (1-2) ◽  
pp. 139-142
Author(s):  
B. Jülich ◽  
G. Gliem ◽  
A. G. S Jánossy
Keyword(s):  
Conformational Changes ◽  
Phosphorus Content ◽  
Chloroplast Development ◽  
Prolamellar Body ◽  
High Electron ◽  
Formation Processes ◽  
Thin Sections ◽  
X Ray ◽  
Transmission Electron ◽  
Phosphorus Containing

Conformational changes of the thylakoid arrangement during light-dependent etioplast-chloroplast development in cotyledons of Nicotiana clevelandii X N. glutinosa are correlated with a decrease of the iron and phosphorus content in electron-dense stroma inclusions. Parallel to the transformation of the prolamellar body and the stacking process of the thylakoids, both the iron and phosphorus content of the inclusions were found to be reduced. Their elemental composition was analysed by means of the energy-dispersive X-ray microanalysis. Due to their high electron-density these stroma inclusions can be observed by conventional transmission electron microscopy in unstained thin-sections from exclusively glutaraldehyde-fixed material. They seem to be involved in membrane formation processes concomitant with the dispersal of the prolamellar bodies. Thus, the iron and phosphorus containing inclusions were found either closely surrounded by membranes or in the intralamellar space of plastids from plantlets illuminated for 1 - 8 hours. In chloroplasts (illumination period 12 -24 hours) no connections between these inclusions and the thylakoids were noticed.

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