F-box protein MdAMR1L1 regulates ascorbate biosynthesis in apple by modulating GDP-mannose pyrophosphorylase

2021 ◽  
Author(s):  
Songya Ma ◽  
Huixia Li ◽  
Lan Wang ◽  
Baiyun Li ◽  
Zhengyang Wang ◽  
...  

Abstract Ascorbate (Asc) is an important antioxidant in plants and humans that plays key roles in various physiological processes. Understanding the regulation of Asc content in fruit plants is important for improving plant resiliency and optimizing Asc in food. Here, we found that both the transcript level and protein abundance of Asc Mannose pathway Regulator 1 Like 1 (MdAMR1L1) was negatively associated with Asc levels during the development of apple (Malus × domestica) fruit. The overexpression or silencing of MdAMR1L1 in apple indicated that MdAMR1L1 negatively regulated Asc levels. However, in the leaves of MdAMR1L1-overexpressing apple lines, the transcript levels of the Asc synthesis gene Guanosine diphosphate-mannose pyrophosphorylase MdGMP1 were increased, while its protein levels and enzyme activity were reduced. This occurred because the MdAMR1L1 protein interacted with MdGMP1 and promoted its degradation via the ubiquitination pathway to inhibit Asc synthesis at the post-translational level. MdERF98, an apple ethylene response factor, whose transcription was modulated by Asc level, is directly bound to the promoter of MdGMP1 to promote the transcription of MdGMP1. These findings provide insights into the regulatory mechanism of Asc biosynthesis in apples and revealed potential opportunities to improve fruit Asc levels.

2020 ◽  
Vol 27 (11) ◽  
pp. 1068-1081
Author(s):  
Xi Liu ◽  
Dongwu Liu ◽  
Yangyang Shen ◽  
Mujie Huang ◽  
Lili Gao ◽  
...  

Matrix Metalloproteinases (MMPs) belong to a family of metal-dependent endopeptidases which contain a series of conserved pro-peptide domains and catalytic domains. MMPs have been widely found in plants, animals, and microorganisms. MMPs are involved in regulating numerous physiological processes, pathological processes, and immune responses. In addition, MMPs play a key role in disease occurrence, including tumors, cardiovascular diseases, and other diseases. Compared with invertebrate MMPs, vertebrate MMPs have diverse subtypes and complex functions. Therefore, it is difficult to study the function of MMPs in vertebrates. However, it is relatively easy to study invertebrate MMPs because there are fewer subtypes of MMPs in invertebrates. In the present review, the structure and function of MMPs in invertebrates were summarized, which will provide a theoretical basis for investigating the regulatory mechanism of MMPs in invertebrates.


Genetics ◽  
1998 ◽  
Vol 149 (3) ◽  
pp. 1205-1219 ◽  
Author(s):  
Jeffrey S Smith ◽  
Carrie Baker Brachmann ◽  
Lorraine Pillus ◽  
Jef D Boeke

Abstract Transcriptional silencing in Saccharomyces cerevisiae occurs at the silent mating-type loci HML and HMR, at telomeres, and at the ribosomal DNA (rDNA) locus RDN1. Silencing in the rDNA occurs by a novel mechanism that depends on a single Silent Information Regulator (SIR) gene, SIR2. SIR4, essential for other silenced loci, paradoxically inhibits rDNA silencing. In this study, we elucidate a regulatory mechanism for rDNA silencing based on the finding that rDNA silencing strength directly correlates with cellular Sir2 protein levels. The endogenous level of Sir2p was shown to be limiting for rDNA silencing. Furthermore, small changes in Sir2p levels altered rDNA silencing strength. In rDNA silencing phenotypes, sir2 mutations were shown to be epistatic to sir4 mutations, indicating that SIR4 inhibition of rDNA silencing is mediated through SIR2. Furthermore, rDNA silencing is insensitive to SIR3 overexpression, but is severely reduced by overexpression of full-length Sir4p or a fragment of Sir4p that interacts with Sir2p. This negative effect of SIR4 overexpression was overridden by co-overexpression of SIR2, suggesting that SIR4 directly inhibits the rDNA silencing function of SIR2. Finally, genetic manipulations of SIR4 previously shown to promote extended life span also resulted in enhanced rDNA silencing. We propose a simple model in which telomeres act as regulators of rDNA silencing by competing for limiting amounts of Sir2 protein.


2017 ◽  
Vol 134 ◽  
pp. 33-44 ◽  
Author(s):  
Rambod Abiri ◽  
Noor Azmi Shaharuddin ◽  
Mahmood Maziah ◽  
Zetty Norhana Balia Yusof ◽  
Narges Atabaki ◽  
...  

2004 ◽  
Vol 14 (11) ◽  
pp. 965-974 ◽  
Author(s):  
Kenneth H Moberg ◽  
Ashim Mukherjee ◽  
Alexey Veraksa ◽  
Spyros Artavanis-Tsakonas ◽  
Iswar K Hariharan
Keyword(s):  

1993 ◽  
Vol 265 (3) ◽  
pp. C680-C687 ◽  
Author(s):  
K. K. Azuma ◽  
C. B. Hensley ◽  
M. J. Tang ◽  
A. A. McDonough

The purpose of this study was to determine the pattern of thyroid hormone (triiodothyronine, T3) regulation of the Na(+)-K(+)-adenosinetriphosphatase (Na(+)-K(+)-ATPase) alpha- and beta-subunit expression in skeletal muscle, which expresses alpha 1-, alpha 2-, beta 1-, and beta 2-subunits, and compare it with that seen in kidney, which expresses only alpha 1 and beta 1. Three steady states were studied: hypothyroid, euthyroid, and hyperthyroid (hypothyroids injected daily with 1 microgram T3/g body wt for 2-16 days). Protein and mRNA abundance, determined by Western and Northern analysis, were normalized to a constant amount of homogenate protein and total RNA, respectively. In skeletal muscle, there was no change in alpha 1- or beta 1-mRNA or protein levels in the transition from hypothyroid to hyperthyroid. However, alpha 2 was highly regulated; mRNA reached a new steady-state level of fivefold over hypothyroid by 8 days of T3 treatment and protein abundance increased threefold. In addition, beta 2-mRNA and protein were detected in skeletal muscle and were also highly regulated by T3; beta 2-mRNA increased nearly fourfold over hypothyroid level, and beta 2-protein abundance increased over twofold. In kidney in the transition from hypothyroid to hyperthyroid, there were coordinate 1.6-fold increases in both alpha 1- and beta 1-mRNA abundance that predicted the observed changes in alpha 1- and beta 1-protein levels and Na(+)-K(+)-ATPase activity.(ABSTRACT TRUNCATED AT 250 WORDS)


2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Mei Ji ◽  
Zhao Zhao ◽  
Yue Li ◽  
Penglin Xu ◽  
Jia Shi ◽  
...  

AbstractRNASET2 (Ribonuclease T2) functions as a tumor suppressor in preventing ovarian tumorigenesis. However, the mechanisms underlying the regulation of RNASET2 protein are completely unknown. Here we identified the F-box protein FBXO6, a substrate recognition subunit of an SCF (Skp1-Cul1-F-box protein) complex, as the ubiquitin E3 ligase for RNASET2. We found that the interaction between FBXO6 and RNASET2 induced RNASET2 instability through the ubiquitin-mediated proteasome degradation pathway. FBXO6 promoted K48-dependent ubiquitination of RNASET2 via its FBA domain. Through analysis of the TCGA dataset, we found that FBXO6 was significantly increased in ovarian cancer tissues and the high expression of FBXO6 was related to the poor overall survival (OS) of ovarian cancer patients at advanced stages. An inverse correlation between the protein levels of FBXO6 and RNASET2 was observed in clinic ovarian cancer samples. Depletion of FBXO6 promoted ovarian cancer cells proliferation, migration, and invasion, which could be partially reversed by RNASET2 silencing. Thus, our data revealed a novel FBXO6-RNASET2 axis, which might contribute to the development of ovarian cancer. We propose that inhibition of FBXO6 might represent an effective therapeutic strategy for ovarian cancer treatment.


2018 ◽  
Author(s):  
Jürgen Jänes ◽  
Yan Dong ◽  
Michael Schoof ◽  
Jacques Serizay ◽  
Alex Appert ◽  
...  

AbstractAn essential step for understanding the transcriptional circuits that control development and physiology is the global identification and characterization of regulatory elements. Here we present the first map of regulatory elements across the development and ageing of an animal, identifying 42,245 elements accessible in at least one C. elegans stage. Based on nuclear transcription profiles, we define 15,714 protein-coding promoters and 19,231 putative enhancers, and find that both types of element can drive orientation-independent transcription. Additionally, hundreds of promoters produce transcripts antisense to protein coding genes, suggesting involvement in a widespread regulatory mechanism. We find that the accessibility of most elements is regulated during development and/or ageing and that patterns of accessibility change are linked to specific developmental or physiological processes. The map and characterization of regulatory elements across C. elegans life provides a platform for understanding how transcription controls development and ageing.


Genetics ◽  
2003 ◽  
Vol 165 (1) ◽  
pp. 83-99
Author(s):  
David J Garfinkel ◽  
Katherine Nyswaner ◽  
Jun Wang ◽  
Jae-Yong Cho

Abstract To determine whether homology-dependent gene silencing or cosuppression mechanisms underlie copy number control (CNC) of Ty1 retrotransposition, we introduced an active Ty1 element into a naïve strain. Single Ty1 element retrotransposition was elevated in a Ty1-less background, but decreased dramatically when additional elements were present. Transcription from the suppressing Ty1 elements enhanced CNC but translation or reverse transcription was not required. Ty1 CNC occurred with a transcriptionally active Ty2 element, but not with Ty3 or Ty5 elements. CNC also occurred when the suppressing Ty1 elements were transcriptionally silenced, fused to the constitutive PGK1 promoter, or contained a minimal segment of mostly TYA1-gag sequence. Ty1 transcription of a multicopy element expressed from the GAL1 promoter abolished CNC, even when the suppressing element was defective for transposition. Although Ty1 RNA and TyA1-gag protein levels increased with the copy number of expressible elements, a given element's transcript level varied less than twofold regardless of whether the suppressing elements were transcriptionally active or repressed. Furthermore, a decrease in the synthesis of Ty1 cDNA is strongly associated with Ty1 CNC. Together our results suggest that Ty1 cosuppression can occur post-transcriptionally, either prior to or during reverse transcription.


Plants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1033
Author(s):  
Chunying Wang ◽  
Tingting Lin ◽  
Mengqi Wang ◽  
Xiaoting Qi

Ethylene-responsive elements (EREs), such as the GCC box, are critical for ethylene-regulated transcription in plants. Our previous work identified a 19-bp AC-rich element (ACE) in the promoter of bean (Phaseolus vulgaris) metal response element-binding transcription factor 1 (PvMTF-1). Ethylene response factor 15 (PvERF15) directly binds ACE to enhance PvMTF-1 expression. As a novel ERF-binding element, ACE exhibits a significant difference from the GCC box. Here, we demonstrated that ACE serves as an ERE in Arabidopsis. It conferred the minimal promoter to respond to the ethylene stress and inhibition of ethylene. Moreover, the cis-acting element ACE could specifically bind the nuclear proteins in vitro. We further revealed that the first 9-bp sequence of ACE (ACEcore) is importantly required by the binding of nuclear proteins. In addition, PvERF15 and PvMTF-1 were strongly induced by ethylene in bean seedlings. Since PvERF15 activates PvMTF-1 via ACE, ACE is involved in ethylene-induced PvMTF-1 expression. Taken together, our findings provide genetic and biochemical evidence for a new ERE.


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