Date of Completion

Spring 5-6-2024

Thesis Advisor(s)

Barbara Mellone

Honors Major

Molecular and Cell Biology

Disciplines

Genetics | Molecular Genetics

Abstract

The centromere, an essential locus on the chromosome critically important for faithful chromosome segregation during cell division, requires the incorporation of centromere protein A (CENP-A/CID) orchestrated by the chaperone CAL1. This thesis investigates the structural requirements governing the interaction between CAL1 and CID, with a focus on two diverged Drosophila species. Using a combination of structural analysis prediction and cellular assays, I explored the compatibility between the N-terminal region of CAL1 and the L1 domain of CID. Previous results demonstrate species specific interactions between CAL1 and CID, with endogenous Drosophila melanogaster (mel) CAL1 efficiently depositing Drosophila melanogaster CID at centromeres, while exogenous CID from Drosophila bipectinata (bip) exhibits mislocalization in mel S2 cells. Mutagenesis aimed at restoring the length of the L1 domain in bip CID did not rescue its centromeric localization, suggesting that the length of L1 is not critical for CID’s recruitment to the centromeres and that additional factors within the L1 must be at play. Additional investigation into the role of specific residues within the N-terminal region of CAL1 reveals that substituting residues at positions 14, 21, 25, and 29 of mel CAL1 with the corresponding residues of bip CAL1 does not result in the centromeric recruitment of bip CID. This suggests that the presence of other residues in CAL1’s N-terminus that are critical for its functional interaction with CID’s L1. These findings highlight the complexity of the CAL1/CID functional interaction and the need for further investigation into the structural determinants governing CID incorporation.

Download

Share

COinS