Deciphering the Functional Collaboration of Mid and bric-a-brac 2 as Potential Regulators of Cellular Proliferation Within Adult <i>Drosophila</i> Ovaries

<p>Stem cell niches are highly organized and specialized microenvironments located within specific tissues of both vertebrate and invertebrate organisms [1]. In <em>Drosophila melanogaster</em>, three distinct stem cell niches have been identified within the ovary including the germline stem cell (GSC), follicle stem cell (FSC), and escort stem cell (ESC) niche. Recently, Fregoso-Lomas et al. [2] reported that Gurken/Epidermal Growth Factor Receptor (EGFR) signaling is modulated within posterior ovarian follicle cells by Midline (Mid). The <em>mid</em> gene encodes a T-box transcription factor protein that specifies cell fates in the developing heart [3][4], central nervous system [5][6], epidermis [7], and eye of <em>Drosophila</em> [8]. The <em>Tbx20</em> gene represents the conserved vertebrate ortholog of <em>mid</em>. Experimental evidence suggests that Tbx20 regulates cell proliferation within the embryonic chamber of the mouse myocardium; <em>Tbx20</em>^-/- null mice exhibit increased expression of <em>Tbx2</em> with a concomitant decrease in <em>N-myc-1 </em>expression, a proto-oncogene. These disturbed signaling events induce hypoplasia [9].</p> <p>The Leal lab undertook a genetic modifier screen and discovered that <em>mid</em> interacts with several genes implicated in the control of cellular proliferation including <em>extramacrochaetae</em> (<em>emc</em>)[8] and <em>dFOXO[10]</em>. In addition, the modENCODE consortium identified <em>bric-a-brac-1 </em>and <em>bric-a-brac-2 </em>(<em>bab-1</em> and <em>bab-2</em>) as theoretical <em>mid</em>-interacting genes that encode proteins harboring a BTB/POZ-ZF domain in <em>Drosophila.</em> The BTB/POZ-ZF domain is associated with oncogenic activity in humans [11]. Towards meeting the aims of the Master’s Thesis research, we carried out: 1) loss-of-function (LOF) and gain-of-function (GOF) studies with <em>mid </em>and specific <em>mid-</em>interacting genes within developing egg chambers, 2) cellular proliferation assays, and 3) immunofluorescent studies. Taken together, these studies allowed us to decipher the functional collaboration of <em>mid</em> with either <em>bab</em>-<em>2</em> or <em>bab-1 </em>as a regulator of cellular proliferation within stem cell niches and as a critical gene required for oogenesis.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Masters Thesis

Discipline thesis:degree_discipline

Biological Sciences

Year dc:date.available

2015

Author dc:creator

• Visic, Petra

Contributors dc:contributor

• Sandra M. Leal
• Glen Shearer, Jr
• Alex S. Flynt

• proliferation
• bric-a-brac
• oogenesis
• germarium
• midline
• Cancer Biology
• Cell Biology
• Developmental Biology
• Genetics

Repository record dc:identifier

https://aquila.usm.edu/masters_theses/110

OAI identifier oai:identifier

oai:aquila.usm.edu:masters_theses-1100