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Student Class

2027

Author ORCID Identifier

orcid.org/0009-0008-8197-7062

First Advisor

Bing He

First Advisor Department

Department of Biological Sciences

Description

Polycomb Repressive Complexes (PRCs) are well known for mediating transcriptional repression, but their potential additional roles in development are less understood. Here, we investigate the function of Posterior sex combs (Psc), a core PRC1 component, in regulating spindle orientation during Drosophila embryogenesis. Focusing on the sieve alleles of Psc, which exhibit maternal-effect phenotypes, we originally observed that mitotic spindles in a subset of mutant embryos became misoriented relative to the epithelial plane during gastrulation. To uncover the molecular basis of this phenotype, we examined the localization of Discs large 1 (Dlg1), an apical-basal polarity protein critical for spindle orientation. In sieve mutants, Dlg1 retained its typical lateral membrane localization with subapical enrichment, but its distribution appeared more heterogeneous across the tissue compared to controls. Our preliminary analysis also revealed abnormal apical enrichment of non-muscle myosin II, suggesting defects in epithelial polarity. Our ongoing work aims to further characterize these polarity defects to identify new mediators of Psc function in spindle orientation. This work extends the known roles of PRC1 beyond transcriptional regulation and, given that loss of epithelial integrity is a hallmark of epithelial cancers, may provide new insights into the mechanistic links between PRC dysfunction and tumorigenesis.

Publication Date

2025

Keywords

Drosophila, embryogenesis, microscopy, ImageJ, Polycomb Repressive Complexes (PRCs), Posterior sex combs (Psc), Discs large 1 (Dlg1), sieve, spindle orientation, myosin II

Disciplines

Cell Biology

Epithelial Mitotic Spindle Orientation Regulation: What Role Does PRC1 Component Psc Play?

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