Identification of avian wax synthases

Area of Science:

• Biochemistry
• Molecular Biology
• Avian Biology

Background:

• Bird species exhibit significant variation in preen gland wax composition.
• Different avian orders (Galliformes, Anseriformes, Strigiformes) utilize distinct wax ester types.
• Wax synthases (WS) catalyze the final step in wax biosynthesis.

Purpose of the Study:

• To identify and characterize wax synthases (WS) in avian species.
• To investigate the functional diversity of WS enzymes in birds.
• To understand the role of WS in avian preen gland secretions.

Main Methods:

• cDNA identification and sequencing of putative WS proteins in chicken, goose, and barn owl.
• Heterologous expression of identified proteins in yeast.
• Enzymatic assays to determine WS activity and substrate specificity.

Main Results:

• Six chicken, two barn owl, and two goose cDNAs encoding putative WS proteins were identified.
• Three chicken proteins exhibited monofunctional WS activity.
• One protein from each species demonstrated bifunctional activity, synthesizing both wax esters and triacylglycerols.
• Monofunctional and bifunctional WS enzymes displayed different substrate specificities, particularly for branched-chain alcohols and acyl-CoA thioesters.
• Avian WS transcripts showed varied expression patterns, suggesting roles beyond preen glands.

Conclusions:

• Avian preen glands possess both monofunctional and bifunctional wax synthases (WS).
• These WS enzymes differ in their expression patterns and substrate specificities.
• The identified WS proteins contribute to the diverse wax ester profiles observed in avian species.