High impact information on desat1

• This is a 16-bp deletion in the 5' region of a desaturase gene (desat2) that was recently suggested to be responsible for the CH polymorphism on the basis of its expression [Dallerac, R., Labeur, C., Jallon, J.-M., Knipple, D. C., Roelofs, W. L. & Wicker-Thomas, C. (2000) Proc. Natl. Acad. Sci. 97, 9449--9454] [1].
• In CS genome, it lies 3.8 kb upstream of desat1 and is not transcribed in either sex [2].
• We first cloned desat1 in the Tai strain and report here functional expression of desat1 in CS and Tai. In both strains, the Desat1 enzymes have the same Delta9 specificity and preferentially use palmitate as a substrate, leading to the synthesis of omega7 fatty acids [2].
• A delta 9 desaturase gene with a different substrate specificity is responsible for the cuticular diene hydrocarbon polymorphism in Drosophila melanogaster [2].
• Also found was a desaturase sequence, named desat2, with a homologous catalytic domain and a markedly different N-terminal domain compared with desat1 [2].

Biological context of desat1

• As the reduction of desat1 activity in the mutant resulted in a large decrease in both unsaturated and saturated FAs, it could impair FA and lipid metabolism, as it is known in vertebrates [3].
• The open reading frame encodes a 380 amino acid (aa) protein with 82% identity to Drosophila melanogaster desat1, and significant (> 50%) identity with other insect delta-9 desaturases [4].
• Both seem to correspond to two distinct genes and have been named "desat locus". They are localized to a single locus, 87C, on the right arm of the third chromosome [5].
• Southern analysis of genomic DNA indicated at least two desaturase gene copies per haploid genome [4].
• The chosen candidate genes presumably contributing to genetic variation in sexual behaviour of Drosophila in the Canyon were desaturase, period, and no-on-transient A. These genes are known to include polymorphic repeated sequences, insertions/deletions, or nucleotide substitutions [6].

Anatomical context of desat1

• We measured the levels of the four desaturase mRNAs in H. zea pheromone glands and larval fat bodies by RT-PCR [7].

Associations of desat1 with chemical compounds

• We have previously shown that a desaturase gene, desat1, located in chromosome region 87 C could be involved in this process: the Desat1 enzyme preferentially leads to the synthesis of palmitoleic acid, a precursor of omega7 fatty acids and 7-unsaturated hydrocarbons [8].

Analytical, diagnostic and therapeutic context of desat1

• This is precisely the position of a desaturase gene previously sequenced using primers derived from yeast and mouse, and localized by in situ hybridization to the polytene chromosomes of D. melanogaster [9].

References