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Identifier 000433412
Title Elucidation of the role of CYP4G genes in insect cuticular hydrocarbon biosynthesis
Alternative Title Αποσαφήνιση του ρόλου CYP4G γονιδίων στη βιοσύνθεση λιπιδίων του εξωσκελετού των εντόμων
Author Παρασύρης, Κωνσταντίνος Α.
Thesis advisor Βόντας, Ιωάννης
Reviewer Χαλεπάκης, Γεώργιος
Siden-Kiamos, Inga
Abstract Hydrocarbons (HCs) act as cuticular waterproofing agents in insects. A pathway of many enzymes facilitates their production: synthases, elongases, desaturases, reductases and CYP4Gs. CYP4Gs catalyze the last step of HC biosynthesis, the decarbonylation reaction that converts the aldehyde-substrate to the hydrocarbon-product. CYP4Gs are members of the cytochrome P450 proteins (P450s) and their genes not only have orthologues distributed across the Insecta, but also there is no CYP4G-like sequence in other organisms; they possess a unique +44 residue insertion. Two CYP4G enzymes are found in Drosophila melanogaster, CYP4G1 and CYP4G15. Despite the fact that CYP4G1 has been studied extensively (catalyzes the insect-specific oxidative decarbonylation step for cuticular HCs production and has significant role in desiccation resistance), no information about the functional contribution of this insertion has been suggested. That is why two transgenic flies were created, with a UAS-REGal4 system and the CRISPR-Cas9 genome editing technique, to express deleted forms of the insertion of CYP4G1 under a null-CYP4G1wt background. In addition, little details about CYP4G15 are available; its localization is different than CYP4G1 (brain vs oenocytes) and its function is unknown. Again, a UASREGal4 system was developed for the purpose of creating flies with simultaneous oenocyte-specific knock down of Cyp4g1 and CYP4G15 expression. Lastly, the malaria vector Anopheles gambiae, like Drosophila, has two CYP4G enzymes; CYP4G16 and CYP4G17. Both enzymes are localized in the oenocytes, having though distinct subcellular localizations at the adult stage, and both act as oxidative decarbonylases. However, an in depth biochemical characterization of CYP4G enzymes (substrate specificities, enzyme kinetics, catalysis) has never been conducted so far. For this reason, expression of recombinant CYP4Gs was tested under various parameters (culture conditions, expression vectors, gene sequence etc.) in the heterologous system of Escherichia coli.
Language English
Subject Cuticle
Issue date 2020-11-27
Collection   School/Department--School of Sciences and Engineering--Department of Biology--Post-graduate theses
  Type of Work--Post-graduate theses
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