Submission Date

4-28-2025

Document Type

Paper- Restricted to Campus Access

Department

Biology

Adviser

Rebecca Lyczak

Committee Member

Susan Adam

Committee Member

Jennifer Gabel

Department Chair

Denise Finney

Project Description

Transparent nematodes like Caenorhabditis elegans (C. elegans) are useful for studying early embryonic processes like mitosis and meiosis. For cells to divide, they must go through the process of mitosis properly. The separation of chromosomes is achieved by the spindles in mitosis, and the spindles are organized by the centrosomes. When mitosis goes wrong, problems like cancer may arise. In C. elegans, the pam-1 gene encodes for a puromycin sensitive aminopeptidase (PAM-1) that belongs to the M1 aminopeptidase family. When pam-1 is mutant in C. elegans, there is a higher occurrence of symmetrical division during mitosis, and the centrosomes move prematurely. PAM-1 is required to prevent premature centrosome movements and to properly attach the chromosomes to the mitotic spindle. Additionally, the absence of PAM-1 triggers the spindle assembly checkpoint. The wee-1.3(lz5) suppressor has been known to rescue some of the defects observed in pam-1 mutant C. elegans, such as improper cell division and low hatch rate. Proteins like β-tubulin, SPD-2, and SPD-5 are important for the spindle structures in C. elegans. Based on previous findings specific to the centrosomes of mutant embryos, a cell cycle regulator, CDK-1, is suspected to be important for centrosome regulation. Through the marking of these proteins with GFP and RFP, antibody staining, and the creation of a new strain, the effect of pam-1, CDK-1, and wee-1.3(lz5) on the embryos of C. elegans during the first mitosis was studied primarily using confocal microscopy. So far, it has been seen that pam-1 mutant embryos took longer than wildtype embryos to orient the spindle and to begin cytokinesis, and the mutant embryos were more likely to experience defects with the tubulin structures. It has also been seen that pam-1 mutant embryos had larger centrosomes than wildtype early in the cell cycle, and SPD-2::GFP and SPD-5::RFP intensity levels sometimes differed depending on the timepoint in the cell cycle. Overall, this research aims to improve the understanding of the mitotic spindles and centrosomes in pam-1 mutant embryos of C. elegans.

Comments

Funded by the NIH (Grant ID: 2R15GM110614-03).

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