scholarly journals Cloning and characterization of a maize cytochrome-b5 reductase withFe3+-chelate reduction capability

1999 ◽  
Vol 338 (2) ◽  
pp. 499-505 ◽  
Author(s):  
Paolo BAGNARESI ◽  
Séverine THOIRON ◽  
Monique MANSION ◽  
Michel ROSSIGNOL ◽  
Paolo PUPILLO ◽  
...  
Keyword(s):  
Iron Reduction ◽  
Molecular Level ◽  
Cytochrome B5 ◽  
Functional Assay ◽  
Sequence Information ◽  
Cytochrome B5 Reductase ◽  
Maize Roots ◽  
First Time ◽  
Translational Mechanisms

We previously purified an NADH-dependent Fe3+-chelate reductase (NFR) from maize roots with biochemical features of a cytochrome-b5 reductase (b5R) [Sparla, Bagnaresi, Scagliarini and Trost (1997) FEBS Lett. 414, 571–575]. We have now cloned a maize root cDNA that, on the basis of sequence information, calculated parameters and functional assay, codes for NFR. Maize NFR has 66% and 65% similarity to mammal and yeast b5R respectively. It has a deduced molecular mass of 31.17 kDa and a pI of 8.53. An uncharged region is observed at its N-terminus but no myristoylation consensus site is present. Taken together, these results, coupled with previous biochemical evidence, prove that NFR belongs to the b5R class and document b5R from a plant at the molecular level for the first time. We have also identified a putative Arabidopsis thaliana NFR gene. Its organization (nine exons) closely resembles mammalian b5Rs. Several NFR isoforms are expected to exist in maize. They are probably not produced by alternative translational mechanisms as occur in mammals, because of specific constraints observed in the maize NFR cDNA sequence. In contrast with yeast and mammals, tissue-specific and various subcellular localizations of maize b5R isoforms could result from differential expression of the various members of a multigene family. The first molecular characterization of a plant b5R indicates an overall remarkable evolutionary conservation for these versatile reductase systems. In addition, the well-characterized Fe3+-chelate reduction capabilities of NFR, in addition to known Fe3+-haemoglobin reduction roles for mammal b5R isoforms, suggest further and more generalized roles for the b5R class in endocellular iron reduction.

scholarly journals De novo assembly and inferred functional annotation of the transcriptome of Heterosigma akashiwo

2022 ◽  
Author(s):  
Masanao Sato ◽  
Masahide Seki ◽  
Yutaka Suzuki ◽  
Shoko Ueki
Keyword(s):  
Functional Annotation ◽  
De Novo ◽  
Molecular Level ◽  
Transcriptome Assembly ◽  
Practical Interest ◽  
Heterosigma Akashiwo ◽  
Sequence Information ◽  
Biological Characterization ◽  
Nucleotide Database

Heterosigma akashiwo is a eukaryotic, cosmopolitan, and unicellular alga (class: Raphidophyceae), and produces fish-killing blooms. There is a substantial scientific and practical interest in its ecophysiological characteristics that determine bloom dynamics and its adaptation to broad climate zones. A well-annotated genomic/genetic sequence information enables researchers to characterize organisms using modern molecular technology. The Chloroplast and the mitochondrial genome sequences and transcriptome sequence assembly (TSA) datasets with limited sizes for H. akashiwo are available in NCBI nucleotide database on December 2021: there is no doubt that more genetic information of the species will greatly enhance the progress of biological characterization of the species. Here, we conducted H. akashiwo RNA sequencing, a de novo transcriptome assembly (NCBI TSA ICRV01) of a large number of high-quality short-read sequences, and the functional annotation of predicted genes. Based on our transcriptome, we confirmed that the organism possesses genes that were predicted to function in phagocytosis, supporting the earlier observations of H. akashiwo bacterivory. Along with its capability for photosynthesis, the mixotrophy of H. akashiwo may partially explain its high adaptability to various environmental conditions. Our study here will provide an important toehold to decipher H. akashiwo ecophysiology at a molecular level.

scholarly journals De novo assembly and inferred functional annotation of the transcriptome of Heterosigma akashiwo

2022 ◽  
Author(s):  
Masanao Sato ◽  
Masahide Seki ◽  
Yutaka Suzuki ◽  
Shoko Ueki
Keyword(s):  
Functional Annotation ◽  
De Novo ◽  
Molecular Level ◽  
Transcriptome Assembly ◽  
Practical Interest ◽  
Heterosigma Akashiwo ◽  
Sequence Information ◽  
Biological Characterization ◽  
Nucleotide Database

Heterosigma akashiwo is a eukaryotic, cosmopolitan, and unicellular alga (class: Raphidophyceae), and produces fish-killing blooms. There is a substantial scientific and practical interest in its ecophysiological characteristics that determine bloom dynamics and its adaptation to broad climate zones. A well-annotated genomic/genetic sequence information enables researchers to characterize organisms using modern molecular technology. The Chloroplast and the mitochondrial genome sequences and transcriptome sequence assembly (TSA) datasets with limited sizes for H. akashiwo are available in NCBI nucleotide database on December 2021: there is no doubt that more genetic information of the species will greatly enhance the progress of biological characterization of the species. Here, we conducted H. akashiwo RNA sequencing, a de novo transcriptome assembly (NCBI TSA ICRV01) of a large number of high-quality short-read sequences, and the functional annotation of predicted genes. Based on our transcriptome, we confirmed that the organism possesses genes that were predicted to function in phagocytosis, supporting the earlier observations of H. akashiwo bacterivory. Along with its capability for photosynthesis, the mixotrophy of H. akashiwo may partially explain its high adaptability to various environmental conditions. Our study here will provide an important toehold to decipher H. akashiwo ecophysiology at a molecular level.

Transcriptional and translational mechanisms of cytochrome b5 reductase isoenzyme generation in humans

2001 ◽  
Vol 355 (2) ◽  
pp. 529-535 ◽  
Author(s):  
Alena LEROUX ◽  
Luisa MOTA VIEIRA ◽  
Axel KAHN
Keyword(s):  
Cytochrome B5 ◽  
Protein Isoforms ◽  
In Vitro Translation ◽  
Alu Elements ◽  
Cytochrome B5 Reductase ◽  
Dynamic Events ◽  
Membrane Bound ◽  
Essential Enzyme ◽  
Translational Mechanisms

Cytochrome b5 reductase (b5R) is an essential enzyme that exists in soluble and membrane-bound isoforms, each with specific functions. In the rat, the two forms are generated from alternative transcripts differing in the first exons. In contrast, the biogenesis of b5R isoforms in the human is not yet well understood. In the present study we have detected three novel alternative exons, designated 1S, S′ and 1B, located between the first alternative exon 1M and the common second exon in the human b5R gene. Accordingly, multiple M-type, S-type and SS′-type and B-type transcripts are generated. All types of human b5R transcript are expressed ubiquitously. An analysis of in vitro translation products demonstrated an alternative use of different AUG initiators resulting in the production of various human b5R protein isoforms. Our results indicate that the organization of the 5′ region of the b5R gene is not conserved between rodents and humans. Insertion of Alu elements into the human b5R gene, in particular just upstream of the S/S′ region, could be responsible for dynamic events of gene rearrangement during evolution.

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