Date of Award

2026

Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy in Biological Sciences (PhD)

Administrative Home Department

Department of Biological Sciences

Advisor 1

Paul D. Goetsch

Committee Member 1

Stephen Techtmann

Committee Member 2

Thomas Werner

Committee Member 3

Xiaohu Tang

Committee Member 4

Caryn L. Heldt

Abstract

The molecular machinery that control the eukaryotic cell cycle, specifically the processes that mediate the switch between cellular division or quiescence, are essential for cellular and organismal viability. However, how the same machinery integrates with developmental or differentiation programs is less well understood. In Caenorhabditis elegans, the 8-subunit DRM complex (for Dp, Rb and MuvB), whose subunits belong to the Synthetic Mulitivulva (SynMuv) B class genes, is a central regulator of the cell cycle but also prevents inappropriate cell fate specification. The conserved mammalian DREAM complex (for Dp, Rb, E2F, And MuvB) is best known as a transcriptional repressor that redundantly prevents cell cycle gene expression with the Retinoblastoma protein to establish cellular quiescence. In C. elegans, the DRM complex, along with other SynMuv B class genes of chromatin- and transcription-associated regulators, also regulate developmental programs associated with vulval cell fate and the germline/soma distinction. Here, we sought to engineer the C. elegans genetic system as a platform for assaying DREAM complex formation and function to better understand how the DREAM complex regulates cell cycle and developmental programs. First, we adapted our current understanding of C. elegans ecological niche, specifically regarding the interactions of C. elegans phenotype analyses with food source, which established a new vector for identifying bioactive secondary metabolites for the development of new therapeutics. Next, we established how the protein interference Auxin-Inducible Degron (AID) system enabled by CRISPR/Cas9-mediated genome editing, which revealed weaknesses in the interpretability of traditional genetic analyses of transcriptional systems. Finally, we explored integrating viral proteins that disrupt DREAM complex function into the C. elegans genome using CRISPR-Cas9/mediated genome editing with the aim to test their mechanism of action. Altogether, the approaches established here provide a foundation for further systematic dissection of DREAM complex function in vivo, establishing new avenues to interrogate the conserved mechanisms that underlie cell cycle control, cell fate decisions, and organismal development.

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Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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