Examining the role of Mco4 in Drosophila iron transport.

• Author / Creator

  Abd Elhafiz, Areeg

• Iron is involved in many aspects of life and is essential for survival and normal development. The role of iron in the body is crucial for many processes, including oxygen transport, steroid hormone synthesis, and DNA repair. However, iron transport in Drosophila melanogaster is less characterized compared to mammalian systems. The mechanism behind how dietary iron is absorbed and transported throughout the body is not entirely clear. Three independent RNA-Seq experiments performed by former Ph.D. students from the King-Jones lab identified significant upregulation of the Drosophila melanogaster gene multicopper oxidase 4 (Mco4) under iron-deprived conditions. This signifies Mco4's possible involvement in the cell's response to low iron conditions. Mco4 is the ortholog of yeast Fet3 and is predicted to encode a multicopper ferroxidase. Fet3p works in conjunction with the transport protein Ftr1p and is required for high affinity iron import. Accordingly, this thesis proposes Mco4 to function as a high affinity iron importer under low iron conditions in Drosophila. The cellular localization and tissue distribution of Mco4 has not been reported before. Therefore, I generated an ex vivo overexpression construct and a transgenic line to study the localization of Mco4 in cells and tissues. In both experiments, I found Mco4 to be localized in the cell membrane, similar to its ortholog Fet3p. To further understand its function, I generated a complete Mco4-loss-of-function line using CRISPR/Cas9. Analysis of the Mco4 null mutant flies was found to significantly reduce the survival rate when these mutants were reared on a low iron diet. To my knowledge, this is the first time a complete loss of Drosophila Mco4 function has been reported. Based on these findings, it would seem likely for Mco4 to play a key role in the cell's response to low iron levels as a potential ferroxidase.

• Subjects / Keywords

  • Iron transport
  • High affinity iron import
  • Mco4
  • Multicopper oxidase
  • Drosophila
  • Fet3

• Graduation date

  Spring 2022

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-298t-pt89

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.