Identification, Gene Structure, and Expression of BnMicEmUP: A Gene Upregulated in Embryogenic Brassica napus Microspores

Microspores of Brassica napus can be diverted from normal pollen development into embryogenesis by treating them with a mild heat shock. As microspore embryogenesis closely resembles zygotic embryogenesis, it is used as model for studying the molecular mechanisms controlling embryo formation. A previous study comparing the transcriptomes of three-day-old sorted embryogenic and pollen-like (non-embryogenic) microspores identified a gene homologous to AT1G74730 of unknown function that was upregulated 8-fold in the embryogenic cells. In the current study, the gene was isolated and sequenced from B. napus and named BnMicEmUP (B. napus microspore embryogenesis upregulated gene). Four forms of BnMicEmUP mRNA and three forms of genomic DNA were identified. BnMicEmUP2,3 was upregulated more than 7-fold by day 3 in embryogenic microspore cultures compared to non-induced cultures. BnMicEmUP1,4 was highly expressed in leaves. Transient expression studies of BnMicEmUP3::GFP fusion protein in Nicotiana benthamiana and in stable Arabidopsis transgenics showed that it accumulates in chloroplasts. The features of the BnMicEmUP protein, which include a chloroplast targeting region, a basic region, and a large region containing 11 complete leucine-rich repeats, suggest that it is similar to a bZIP PEND (plastid envelope DNA-binding protein) protein, a DNA binding protein found in the inner envelope membrane of developing chloroplasts. Here, we report that the BnMicEmUP3 overexpression in Arabidopsis increases the sensitivity of seedlings to exogenous abscisic acid (ABA). The BnMicEmUP proteins appear to be transcription factors that are localized in plastids and are involved in plant responses to biotic and abiotic environmental stresses; as well as the results obtained from this study can be used to improve crop yield.

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Switch-like control of helicase processivity by single-stranded DNA binding protein

10.1101/2020.07.09.194779 ◽

2020 ◽

Author(s):

Barbara Stekas ◽

Masayoshi Honda ◽

Maria Spies ◽

Yann R. Chemla

Keyword(s):

Dna Binding ◽

Single Molecule ◽

Molecular Mechanisms ◽

Binding Protein ◽

Optical Trap ◽

Dna Binding Protein ◽

Single Stranded Dna ◽

Associated Proteins ◽

Underlying Mechanisms ◽

Xpd Helicase

Helicases utilize the energy of NTP hydrolysis to translocate along single-stranded nucleic acids (NA) and unwind the duplex. In the cell, helicases function in the context of other NA-associated proteins which regulate helicase function. For example, single-stranded DNA binding proteins are known to enhance helicase activity, although the underlying mechanisms remain largely unknown. F. acidarmanus XPD helicase serves as a model for understanding the molecular mechanisms of Superfamily 2B helicases, and previous work has shown that its activity is enhanced by the cognate single-stranded DNA binding protein RPA2. Here, single-molecule optical trap measurements of the unwinding activity of a single XPD helicase in the presence of RPA2 reveal a mechanism in which XPD interconverts between two states with different processivities and transient RPA2 interactions stabilize the more processive state, activating a latent “processivity switch” in XPD. These findings provide new insights on mechanisms of helicase regulation by accessory proteins.

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Neurotoxic 43-kDa TAR DNA-binding Protein (TDP-43) Triggers Mitochondrion-dependent Programmed Cell Death in Yeast

Journal of Biological Chemistry ◽

10.1074/jbc.m110.194852 ◽

2011 ◽

Vol 286 (22) ◽

pp. 19958-19972 ◽

Cited By ~ 56

Author(s):

Ralf J. Braun ◽

Cornelia Sommer ◽

Didac Carmona-Gutierrez ◽

Chamel M. Khoury ◽

Julia Ring ◽

...

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Dna Binding ◽

Molecular Mechanisms ◽

Binding Protein ◽

Cell Loss ◽

Dna Binding Protein ◽

Respiratory Capacity ◽

Endonuclease G ◽

Markers Of Oxidative Stress

Pathological neuronal inclusions of the 43-kDa TAR DNA-binding protein (TDP-43) are implicated in dementia and motor neuron disorders; however, the molecular mechanisms of the underlying cell loss remain poorly understood. Here we used a yeast model to elucidate cell death mechanisms upon expression of human TDP-43. TDP-43-expressing cells displayed markedly increased markers of oxidative stress, apoptosis, and necrosis. Cytotoxicity was dose- and age-dependent and was potentiated upon expression of disease-associated variants. TDP-43 was localized in perimitochondrial aggregate-like foci, which correlated with cytotoxicity. Although the deleterious effects of TDP-43 were significantly decreased in cells lacking functional mitochondria, cell death depended neither on the mitochondrial cell death proteins apoptosis-inducing factor, endonuclease G, and cytochrome c nor on the activity of cell death proteases like the yeast caspase 1. In contrast, impairment of the respiratory chain attenuated the lethality upon TDP-43 expression with a stringent correlation between cytotoxicity and the degree of respiratory capacity or mitochondrial DNA stability. Consistently, an increase in the respiratory capacity of yeast resulted in enhanced TDP-43-triggered cytotoxicity, oxidative stress, and cell death markers. These data demonstrate that mitochondria and oxidative stress are important to TDP-43-triggered cell death in yeast and may suggest a similar role in human TDP-43 pathologies.

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GSBF1, a seedling-specific bZIP DNA-binding protein with preference for a ?split? G-box-related element in Brassica napus RbcS promoters

Plant Molecular Biology ◽

10.1007/bf00020204 ◽

1996 ◽

Vol 32 (4) ◽

pp. 631-639 ◽

Cited By ~ 10

Author(s):

Stephan Waldm�ller ◽

Ulrike M�ller ◽

Gerhard Link

Keyword(s):

Brassica Napus ◽

Dna Binding ◽

Binding Protein ◽

Dna Binding Protein ◽

Related Element

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The role of TDP-43 propagation in neurodegenerative diseases: integrating insights from clinical and experimental studies

Experimental & Molecular Medicine ◽

10.1038/s12276-020-00513-7 ◽

2020 ◽

Vol 52 (10) ◽

pp. 1652-1662

Author(s):

Myungjin Jo ◽

Shinrye Lee ◽

Yu-Mi Jeon ◽

Seyeon Kim ◽

Younghwi Kwon ◽

...

Keyword(s):

Dna Binding ◽

Neurodegenerative Diseases ◽

Molecular Mechanisms ◽

Binding Protein ◽

Experimental Studies ◽

Amyloid Β ◽

Dna Binding Protein ◽

Age Related ◽

The Central Nervous System ◽

Novel Therapeutic Strategies

Abstract TAR DNA-binding protein 43 (TDP-43) is a highly conserved nuclear RNA/DNA-binding protein involved in the regulation of RNA processing. The accumulation of TDP-43 aggregates in the central nervous system is a common feature of many neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), Alzheimer’s disease (AD), and limbic predominant age-related TDP-43 encephalopathy (LATE). Accumulating evidence suggests that prion-like spreading of aberrant protein aggregates composed of tau, amyloid-β, and α-synuclein is involved in the progression of neurodegenerative diseases such as AD and PD. Similar to those of prion-like proteins, pathological aggregates of TDP-43 can be transferred from cell-to-cell in a seed-dependent and self-templating manner. Here, we review clinical and experimental studies supporting the prion-like spreading of misfolded TDP-43 and discuss the molecular mechanisms underlying the propagation of these pathological aggregated proteins. The idea that misfolded TDP-43 spreads in a prion-like manner between cells may guide novel therapeutic strategies for TDP-43-associated neurodegenerative diseases.

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Switch-like control of helicase processivity by single-stranded DNA binding protein

eLife ◽

10.7554/elife.60515 ◽

2021 ◽

Vol 10 ◽

Author(s):

Barbara Stekas ◽

Steve Yeo ◽

Alice Troitskaia ◽

Masayoshi Honda ◽

Sei Sho ◽

...

Keyword(s):

Dna Binding ◽

Molecular Mechanisms ◽

Binding Protein ◽

Optical Trap ◽

Dna Binding Protein ◽

Single Stranded Dna ◽

Associated Proteins ◽

Underlying Mechanisms ◽

Regulatory Dna ◽

Xpd Helicase

Helicases utilize NTP hydrolysis to translocate along single-stranded nucleic acids (NA) and unwind the duplex. In the cell, helicases function in the context of other NA-associated proteins such as single-stranded DNA binding proteins. Such encounters regulate helicase function, although the underlying mechanisms remain largely unknown. F. acidarmanus XPD helicase serves as a model for understanding the molecular mechanisms of Superfamily 2B helicases, and its activity is enhanced by the cognate single-stranded DNA binding protein RPA2. Here, optical trap measurements of the unwinding activity of a single XPD helicase in the presence of RPA2 reveal a mechanism in which XPD interconverts between two states with different processivities and transient RPA2 interactions stabilize the more processive state, activating a latent 'processivity switch' in XPD. A point mutation at a regulatory DNA binding site on XPD similarly activates this switch. These findings provide new insights on mechanisms of helicase regulation by accessory proteins.

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