Reference: Husselstein T, et al. (1999) Delta7-sterol-C5-desaturase: molecular characterization and functional expression of wild-type and mutant alleles. Plant Mol Biol 39(5):891-906

Reference Help

Abstract


An Arabidopsis thaliana recessive monogenic mutant (ste1-1) presenting a deficiency of the delta7-sterol-C5(6)-desaturase step in the sterol pathway has been reported previously [12]. To further characterize ste1-1, Arabidopsis, Nicotiana tabacum and Homo sapiens cDNAs encoding delta7-sterol-C5(6)-desaturases were isolated and identified on the basis of their ability to restore ergosterol synthesis in erg3, a yeast null mutant whose gene encoding the delta7-sterol-C5(6)-desaturase was disrupted. Overexpression of the Arabidopsis cDNA driven by a 35S promoter in transgenic ste1-1 plants led to full complementation of the mutant. This result demonstrates that STE1 was the impaired component in the desaturation system. Four independent reverse transcriptions of ste1-1 RNA followed by polymerase chain reactions (RT-PCRs), yielded a single product. Alignment of the wild-type ORF with the RT-PCR derived ste1-1 ORF revealed a single amino acid substitution: Thr-114 in the wild-type is changed to Ile in ste1-1. Expression in erg3 resulted in a 6-fold lowered efficiency of the ste1-1 ORF in complementing the yeast biosynthetic pathway when compared to the wild-type ORF. The presence of this mutation in the mutant ste1-1 genomic sequence (and no additional modification between ste1-1 and wild-type genes) demonstrates that the change of the Thr-114 to Ile is necessary and sufficient to create the leaky allele ste1-1. The occurrence of a hydroxylated amino acid (Thr or Ser) at the position corresponding to Thr-114 in the five delta7-sterol-C5(6)-desaturases identified so far suggests that this amino acid is important for normal enzymatic function.

Reference Type
Journal Article
Authors
Husselstein T, Schaller H, Gachotte D, Benveniste P
Primary Lit For
Additional Lit For
Review For

Interaction Annotations


Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details about experiment type and any other genes involved in the interaction.

Interactor Interactor Type Assay Annotation Action Modification Phenotype Source Reference

Gene Ontology Annotations


Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table.

Gene Gene Ontology Term Qualifier Aspect Method Evidence Source Assigned On Annotation Extension Reference

Phenotype Annotations


Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details.

Gene Phenotype Experiment Type Mutant Information Strain Background Chemical Details Reference

Regulation Annotations


Increase the total number of rows displayed on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; to filter the table by a specific experiment type, type a keyword into the Filter box (for example, “microarray”); download this table as a .txt file using the Download button or click Analyze to further view and analyze the list of target genes using GO Term Finder, GO Slim Mapper, SPELL, or YeastMine.

Regulator Target Experiment Assay Construct Conditions Strain Background Reference