Related Experiment Video

Updated: Jul 17, 2026

Induction and Diagnosis of Tumors in Drosophila Imaginal Disc Epithelia
08:14

Induction and Diagnosis of Tumors in Drosophila Imaginal Disc Epithelia

Published on: July 25, 2017

The Drosophila tumor suppressors Expanded and Merlin differentially regulate cell cycle exit, apoptosis, and Wingless

Brett J Pellock1, Eugene Buff, Kristin White

  • 1Massachusetts General Hospital Cutaneous Biology Research Center, Charlestown, MA 02129, and University of California, Berkeley, Department of Molecular and Cell Biology 94720, USA.

Developmental Biology
|January 30, 2007
PubMed

Insights

Mutations in merlin (mer) and expanded (ex) genes impact Drosophila cell growth. These proteins, part of the Band 4.1 superfamily, differentially regulate cell proliferation, survival, and Wingless signaling.

Area of Science:

  • Cell Biology
  • Developmental Biology
  • Genetics

Background:

  • Merlin (mer) and expanded (ex) are Band 4.1 superfamily proteins implicated in regulating cell growth and proliferation in Drosophila.
  • Previous studies suggested mer and ex function redundantly upstream of the Hippo (Hpo) and Warts (Wts) pathway.

Purpose of the Study:

  • To investigate the distinct roles of merlin and expanded in regulating cell proliferation, survival, and downstream signaling pathways.
  • To elucidate the differential functions of mer and ex beyond their proposed redundant roles.

Main Methods:

  • Analysis of individual mer and ex mutant phenotypes in Drosophila.
  • Examination of cell cycle progression and apoptosis in developing eye and pupal retina.
  • Assessment of Wingless protein levels in the eye.

Main Results:

  • Both mer and ex mutations lead to increased cell growth, but exhibit distinct effects on cell cycle exit and apoptosis.
  • ex mutant clones show delayed cell cycle exit in the eye, while mer mutant clones do not.
  • Loss of mer significantly impairs developmental apoptosis, whereas loss of ex has a milder effect.
  • ex, but not mer or hpo, plays a role in regulating Wingless protein levels in the eye.

Conclusions:

  • Merlin and expanded proteins play distinct, non-redundant roles in regulating cell proliferation and survival.
  • These proteins differentially modulate downstream pathways, including Wingless signaling.
  • The findings highlight the complex regulatory network governing cell growth and division in Drosophila.

More Related Videos

The Drosophila Imaginal Disc Tumor Model: Visualization and Quantification of Gene Expression and Tumor Invasiveness Using Genetic Mosaics10:31

The Drosophila Imaginal Disc Tumor Model: Visualization and Quantification of Gene Expression and Tumor Invasiveness Using Genetic Mosaics

Published on: October 6, 2016

A Protocol for Genetic Induction and Visualization of Benign and Invasive Tumors in Cephalic Complexes of Drosophila melanogaster07:23

A Protocol for Genetic Induction and Visualization of Benign and Invasive Tumors in Cephalic Complexes of Drosophila melanogaster

Published on: September 11, 2013

Related Concept Videos

Canonical Wnt Signaling Pathway02:54

Canonical Wnt Signaling Pathway

The gene encoding the main signaling molecules of the Wnt signaling pathways (the Wnt proteins) was discovered almost four decades ago by Nüsslein-Volhard and Wieschaus. They identified and originally named the gene "wingless" (wg) after a phenotype discovered during their landmark genetic screen in Drosophila for body pattern defects. At around the same time, another researcher named Harold Varmus found that a murine tumor virus activates the mammalian wg homolog, Int-1, which results in tumor...
Abnormal Proliferation02:23

Abnormal Proliferation

Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the daughter...
Negative Regulator Molecules01:23

Negative Regulator Molecules

Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria.
Cancer-Critical Genes II: Tumor Suppressor Genes01:05

Cancer-Critical Genes II: Tumor Suppressor Genes

Genes usually encode proteins necessary for the proper functioning of a healthy cell. Mutations can often cause changes to the gene expression pattern, thereby altering the phenotype.
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...
Interactions Between Signaling Pathways01:19

Interactions Between Signaling Pathways

Signaling cascades usually lack linearity. Multiple pathways interact and regulate one another, allowing cells to integrate and respond to diverse environmental stimuli.
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
Loss of Tumor Suppressor Gene Functions01:12

Loss of Tumor Suppressor Gene Functions

Tumor suppressor genes are normal genes that can slow down cell division, repair DNA mistakes, or program the cells for apoptosis in case of irreparable damage. Hence, they play an essential role in preventing the proliferation of damaged cells.
When the tumor suppressor genes develop mutations or are lost, cells start growing out of control, leading to cancer. However, a single functional copy of the tumor suppressor gene is enough for the cells to maintain their normal functions and cell...