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Literature summary extracted from

  • Wayne, L.L.; Wallis, J.G.; Kumar, R.; Markham, J.E.; Browse, J.
    Cytochrome b5 reductase encoded by CBR1 is essential for a functional male gametophyte in Arabidopsis (2013), Plant Cell, 25, 3052-3066.
    View publication on PubMedView publication on EuropePMC

Protein Variants

EC Number Protein Variants Comment Organism
1.6.2.2 additional information three T-DNA insertional knockout mutants of the gene CBR1 encoding cytochrome b5 reductase showing distorted segregation, with greatly reduced penetrance through the male gametophyte. In fertilization experiments, pollen of cbr1-2 plants germinated on wild-type and cbr1-2 stigmas, but the majority of pollen tubes stopped growing prior to reaching the ovules, leading to severely reduced fertilization and seed set Arabidopsis thaliana

Localization

EC Number Localization Comment Organism GeneOntology No. Textmining
1.6.2.2 endoplasmic reticulum
-
 Arabidopsis thaliana 5783
-
1.6.2.2 microsome
-
 Arabidopsis thaliana
-
-

Natural Substrates/ Products (Substrates)

EC Number Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
1.6.2.2 2 ferricytochrome b5 + NADH Arabidopsis thaliana
-
 2 ferrocytochrome b5 + NAD+ + H+
-
 ?

Organism

EC Number Organism UniProt Comment Textmining
1.6.2.2 Arabidopsis thaliana
-
 gene CBR1
-

Source Tissue

EC Number Source Tissue Comment Organism Textmining

Substrates and Products (Substrate)

EC Number Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
1.6.2.2 2 ferricytochrome b5 + NADH
-
 Arabidopsis thaliana 2 ferrocytochrome b5 + NAD+ + H+
-
 ?

Synonyms

EC Number Synonyms Comment Organism
1.6.2.2 cytochrome b5 reductase
-
 Arabidopsis thaliana
1.6.2.2 NADH:cytochrome b5 reductase
-
 Arabidopsis thaliana

Cofactor

EC Number Cofactor Comment Organism Structure
1.6.2.2 NADH
-
 Arabidopsis thaliana

General Information

EC Number General Information Comment Organism
1.6.2.2 malfunction the progeny of plants heterozygous for the cbr1-2 allele segregate 6% homozygous mutants, while cbr1-3 and cbr1-4 heterozygotes segregate 1:1 heterozygous:wild-type, indicating a gametophyte defect. Homozygous cbr1-2 seeds are deformed and required Suc for successful germination and seedling establishment. Vegetative growth of cbr1-2 plants was relatively normal, and they produced abundant flowers, but very few seeds. The pollen produced in cbr1-2 anthers is viable, but when germinated on cbr1-2 or wild-type stigmas, most of the resulting pollen tubes do not extend into the transmitting tract, resulting in a very low frequency of fertilization, phenotype, overview Arabidopsis thaliana
1.6.2.2 physiological function cytochrome b5 reductase encoded by CBR1 is essential for a functional male gametophyte in Arabidopsis thaliana. It provides electrons, via cytochrome b5, for a range of biochemical reactions in cellular metabolism, including for fatty acid desaturation in the endoplasmic reticulum. Cytochrome b5 reductase is not essential during vegetative growth but is required for correct pollen function and seed maturation Arabidopsis thaliana