Award Date

8-1-2023

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Life Sciences

First Committee Member

Laurel Raftery

Second Committee Member

Andrew Andres

Third Committee Member

Mo Weng

Fourth Committee Member

Hong Sun

Number of Pages

106

Abstract

To understand how complex tissues are formed, we need to understand how cells communicate with other cells to build structures. In Drosophila melanogaster, epithelial cells form tubular structures to shape the dorsal appendages on the eggshells. One signaling pathway needed for this event is the Hippo-like kinase intracellular pathway. I focus on two key components in this pathway: the NDR kinase Tricornered (Trc) and Mob proteins. In eukaryotes, Mob proteins are known to interact with NDR kinases to promote their activation. The Hippo- like pathway involves the NDR kinase Trc; however, the specific Mob protein(s) that interact with Trc are unclear. I studied the functions of Trc, Mob1, Mob2, and Mob4 in several aspects of tube formation using RNA interference (RNAi) in all somatic follicle cells of the ovary in vivo. First, I evaluated the dorsal appendages on the eggshells that were formed by females with reduced levels of Trc, Mob1, or Mob2 and found that these structures were shortened or lengthened compared to controls, and also widened at the base. These phenotypes led me to investigate how the organization of the follicle cell tubes for dorsal appendage formation were affected by RNAi of these gene products. Two types of follicle cells create the dorsal appendages, called roof and floor cells. To visualize the cell organization, I used immunofluorescence and confocal microscopy. I then evaluated the organization of each cell type at the specific stages of oogenesis when the tube structures are formed. I found that floor cell organization was most frequently abnormal. Roof cell organization appeared to be affected rarely. I then evaluated whether components of the STRIPAK complex (an established antagonist of the Hippo pathway) contributed to dorsal appendage formation, using RNAi against core STRIPAK components; Strip, Striatin, and Mob4. I then examined the dorsal appendages laid by the females with reduced levels of these gene products. RNAi against each component led to similar abnormalities in the dorsal appendages. These results indicated that STRIPAK also plays a role in proper dorsal appendage formation. This work reveals key components in the morphogenesis of dorsal appendages.

Keywords

Floor Cells; Hippo-like; Mob1; Mob2; Mob4; Roof Cells

Disciplines

Biology | Cell Biology | Developmental Biology

File Format

pdf

File Size

2700 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

Available for download on Saturday, August 15, 2026


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