Cloning and functional expression of a cDNA encoding a pheromone gland-specific acyl-CoA Delta11-desaturase of the cabbage looper moth, Trichoplusia ni.
Desaturation of coenzyme-A esters of saturated fatty acids is a common feature of sex pheromone biosynthetic pathways in the Lepidoptera. The enzymes that catalyze this step share several biochemical properties with the ubiquitous acyl-CoA Delta9-desaturases of animals and fungi, suggesting a common ancestral origin. Unlike metabolic acyl-CoA Delta9-desaturases, pheromone desaturases have evolved unusual regio- and stereoselective activities that contribute to the remarkable diversity of chemical structures used as pheromones in this large taxonomic group. In this report, we describe the isolation of a cDNA encoding a pheromone gland desaturase from the cabbage looper moth, Trichoplusia ni, a species in which all unsaturated pheromone products are produced via a Delta11Z-desaturation mechanism. The largest ORF of the approximately 1,250-bp cDNA encodes a 349-aa apoprotein (PDesat-Tn Delta11Z) with a predicted molecular mass of 40,240 Da. Its hydrophobicity profile is similar overall to those of rat and yeast Delta9-desaturases, suggesting conserved transmembrane topology. A 182-aa core domain delimited by conserved histidine-rich motifs implicated in iron-binding and catalysis has 72 and 58% similarity (including conservative substitutions) to acyl-CoA Delta9Z-desaturases of rat and yeast, respectively. Northern blot analysis revealed an approximately 1,250-nt PDesat-Tn Delta11Z mRNA that is consistent with the spatial and temporal distribution of Delta11-desaturase enzyme activity. Genetic transformation of a desaturase-deficient strain of the yeast Saccharomyces cerevisiae with an expression plasmid encoding PDesat-Tn Delta11Z resulted in complementation of the strain's fatty acid auxotrophy and the production of Delta11Z-unsaturated fatty acids.
Knipple
D C
DC
Department of Entomology, New York State Agricultural Experiment Station, Cornell University, Geneva, NY 14456, USA.
Rosenfield
C L
CL
Miller
S J
SJ
Liu
W
W
Tang
J
J
Ma
P W
PW
Roelofs
W L
WL
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D017124:Conserved Sequence; D018076:DNA, Complementary; D004702:Endocrine Glands / Q000201:enzymology; D044943:Fatty Acid Desaturases / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D017344:Genes, Insect; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009036:Moths / Q000201:enzymology* / Q000235:genetics; D016366:Open Reading Frames; D010675:Pheromones / Q000378:metabolism; D051381:Rats; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D010675:Pheromones; D044943:Fatty Acid Desaturases