Name: live-imaging of the drosophila pupal eye
Uploaded: 2015-01-12T13:45:00
Description: Watch this Scientific Journal Video about Live-imaging of the Drosophila Pupal Eye at JoVE.com

The authors thank David Larson for developing the original protocol for imaging the live Drosophila pupal eye. We thank our colleagues Richard Carthew, Shoichiro Tsukita and Matthew Freeman, who developed the transgenic flies that we combined to generate our live-imaging fly lines. Brittany Baldwin-Hunter gave helpful comments on the manuscript. This work was supported by start-up funds awarded to Ruth Johnson by Wesleyan University.

Figure 3 shows a summary of the experimental procedure.
1. Tissue Preparation
<ol>
	<li>To determine the consequences of modified expression of a gene of interest, set up the following cross in duplicate and maintain at 25 &#176;C: UAS-transgene (males)X GMR-GAL4; UAS-&#945;-cat:GFP, ubi-DE-Cad:GFP ; + / SM5-TM6b (virgin females) NOTE: To obtain control tissue cross UAS-lacZ males to GMR-GAL4; UAS-&#945;-cat:GFP, ubi-DE-Cad:GFP fe...

<ol>
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The description of wild-type development (above) forms the basis for comparisons of patterning events in RNAi or overexpression genotypes. Comparisons of live tissue development are invaluable when determining precisely which cell behaviors are regulated by a protein of interest. Further, and not described here, live cell imaging enables one to make qualitative and/or quantitative descriptions of the role of a gene of interest in the events that pattern the eye. By 30-32 hr APF most pigment cells have acquired stable pos...

The compound Drosophila eye is characterized by the stereotyped arrangement of its ~750 ommatidia separated by a honeycomb-lattice of accessory pigment cells 4,5. These pigment cells are patterned by a coordinated combination of events: local cell movements, cell growth, changes in cell shape, and apoptosis. Live visualization of this epithelium allows one to study the molecular mechanisms underpinning these events in a physiologically relevant and unperturbed three-dimensional context.
In contrast to previous protocols 6,7, the technique outlined here incorporates an efficient method for stabilizing extraneous tissue movement that cannot be uncoupled from the imaging process. This method enhances studies of cell behavior in the developing Drosophila pupal eye epithelium &#8211; a tissue that grows, rotates, and shifts over the course of imaging. In addition the motion-stabilization technique described here will be useful for studying cells in other contexts where extraneous movement occurs.
To visualize cell boundaries in the Drosophila retinal field, transgenic fly lines were generated that express ubi-DE-Cadherin:GFP as well as UAS-&#945;-catenin:GFP under control of the eye-specific driver GMR-GAL4 1-3. The use of two GFP-tagged membrane markers allows for the visualization of cell boundaries at lower intensity light. This minimizes tissue damage and photobleaching on repeated exposure to high-energy wavelengths, enabling increased frame rate and movie duration. To enhance efficacy of RNAi transgenes, UAS-Dcr-2 was also incorporated into a second fly line 8.
In a third update from previous protocols, a simpler imaging rig that is easily assembled in most laboratories is described. This apparatus obviates the requirement to have a specialized imaging rig generated by a university&#8217;s &#8216;machine shop&#8217; or similar service. This imaging rig is similar to that used to image other pupal tissues 9,10.
Presented here is a simple live-cell imaging protocol that can be used to directly assess the morphogenetic events that contribute to eye patterning from ~17 to 42 hr after puparium formation (hr APF). Specifically, this protocol enables one to determine the consequences of modifying gene expression during pupal development.

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		<tr height="21">
			<td height="21" style="height:21px;width:263px;">Name of Material/ Equipment</td>
			<td style="width:124px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td style="width:167px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td colspan="3" height="21" style="height:21px;">GMR-GAL4; UAS-a-cat:GFP, ubi-DE-Cadherin:GFP ; + / SM5-TM6b</td>
			<td>Available on request from authors</td>
		</tr>
		<tr height="21">
			<td colspan="3" height="21" style="height:21px;">UAS-dcr-2; UAS-a-cat:GFP, ubi-DE-Cadherin:GFP; + / SM5-TM6b&#160;</td>
			<td>Available on request from authors</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:263px;">Scotch double stick tape</td>
			<td style="width:124px;">3M</td>
			<td style="width:119px;">665</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:263px;">Black Sylgard dissection dish</td>
			<td style="width:124px;"></td>
			<td style="width:119px;"></td>
			<td>Fill glass petri dish to rim with Sylgard (colored black with finely-ground charcoal powder) or Sylgard 170; leave at room temperature for 24-48 h to polymerize</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:263px;">Sylgard</td>
			<td style="width:124px;">Dow Corning</td>
			<td style="width:119px;">SYLG184</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:263px;">Sylgard (Black)</td>
			<td style="width:124px;">Dow Corning</td>
			<td style="width:119px;">SYLG170</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:263px;">Glass petri dish</td>
			<td style="width:124px;">Corning</td>
			<td style="width:119px;">7220-85</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:263px;">25 x 75 x 1 mm glass microscope slide</td>
			<td style="width:124px;">Fisher Scientific</td>
			<td style="width:119px;">12-550-413</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:263px;">22 x 40 mm glass coverslip</td>
			<td style="width:124px;">VWR</td>
			<td>48393-172</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:263px;">Forceps&#160;</td>
			<td style="width:124px;">Fine Science Tools</td>
			<td style="width:119px;">91150-20</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:263px;">Whatman 3mm Chromatography Paper</td>
			<td style="width:124px;">Fisher Scientific</td>
			<td style="width:119px;">05-713-336</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:263px;">Vaseline</td>
			<td style="width:124px;">Fisher Scientific</td>
			<td style="width:119px;">19-086-291</td>
			<td>Or purchase at local pharmacy.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:263px;">30ml syringe</td>
			<td style="width:124px;">Fisher Scientific</td>
			<td style="width:119px;">S7510-30</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:263px;">Adobe Photoshop CS5</td>
			<td style="width:124px;">Adobe</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:263px;">Leica TCS SP5 DM microscope</td>
			<td style="width:124px;">Leica Microsystems</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:263px;">LAS AF Version 2.6.0.7266 microscope software</td>
			<td style="width:124px;">Leica Microsystems</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

live-imaging of the drosophila pupal eye

Inherent processes of Drosophila pupal development can shift and distort the eye epithelium in ways that make individual cell behavior difficult to track during live cell imaging. These processes include: retinal rotation, cell growth and organismal movement. Additionally, irregularities in the topology of the epithelium, including subtle bumps and folds often introduced as the pupa is prepared for imaging, make it challenging to acquire in-focus images of more than a few ommatidia in a single focal plane. The workflow outlined here remedies these issues, allowing easy analysis of cellular processes during Drosophila pupal eye development. Appropriately-staged pupae are arranged in an imaging rig that can be easily assembled in most laboratories. Ubiquitin-DE-Cadherin:GFP and GMR-GAL4&#8211;driven UAS-&#945;-catenin:GFP are used to visualize cell boundaries in the eye epithelium 1-3. After deconvolution is applied to fluorescent images captured at multiple focal planes, maximum projection images are generated for each time point and enhanced using image editing software. Alignment algorithms are used to quickly stabilize superfluous motion, making individual cell behavior easier to track.

Live-imaging of the pupal eye is a successful strategy to observe cell behaviors that contribute to patterning of the neuroepithelium. The role of specific proteins can be readily assessed by expressing transgenes that modify protein levels during eye development. To do this GMR-GAL4 is used to drive transgene expression behind the morphogenetic furrow. This offers the advantage of not perturbing earlier events that establish the eye field during the first two larval instars. In addition many RNAi transgenes req...

Watch this Scientific Journal Video about Live-imaging of the Drosophila Pupal Eye at JoVE.com

Live-imaging of the Drosophila Pupal Eye

This protocol presents an efficient method for imaging the live Drosophila pupal eye neuroepithelium. This method compensates for tissue movement and uneven topology, enhances visualization of cell boundaries through the use of multiple GFP-tagged junction proteins, and uses an easily-assembled imaging rig.

Live-imaging of the Drosophila Pupal Eye

Inherent processes of Drosophila pupal development can shift and distort the eye epithelium in ways that make individual cell behavior difficult to track ...

Research

JoVE Journal

Developmental Biology

In Vitro Differentiation of Mature Myofibers for Live Imaging

Skeletal muscles are composed of myofibers, the biggest cells in the mammalian body and one of the few syncytia. How the complex and evolutionarily conserved structures that compose it are assembled remains under investigation. Their size and physiological features often constrain manipulation and imaging applications. The culture of immortalized cell lines is widely used, but it can only replicate the early steps of differentiation.
Here, we describe a protocol that enables easy genetic manipulation of myofibers originating from primary mouse myoblasts. After one week of differentiation, the myofibers display contractility, aligned sarcomeres and triads, as well as peripheral nuclei. The entire differentiation process can be followed by live imaging or immunofluorescence. This system combines the advantages of the existing ex vivo and in vitro protocols. The possibility of easy and efficient transfection as well as the ease of access to all differentiation stages broadens the potential applications. Myofibers can subsequently be used not only to address relevant developmental and cell biology questions, but also to reproduce muscle disease phenotypes for clinical applications.

In Vitro Differentiation of Mature Myofibers for Live Imaging

Muscle cells are among the most complex eukaryotic cells. We present a protocol for the in vitro differentiation of highly mature myofibers that allows for genetic manipulation and clear imaging during all developmental stages.

Skeletal muscles are composed of myofibers, the biggest cells in the mammalian body and one of the few syncytia. How the complex and evolutionarily ...

Long-term Live Imaging of Drosophila Eye Disc

Live imaging provides the ability to continuously track dynamic cellular and developmental processes in real time. Drosophila larval imaginal discs have been used to study many biological processes, such as cell proliferation, differentiation, growth, migration, apoptosis, competition, cell-cell signaling, and compartmental boundary formation. However, methods for the long-term ex vivo culture and live imaging of the imaginal discs have not been satisfactory, despite many efforts. Recently, we developed a method for the long-term ex vivo culture and live imaging of imaginal discs for up to 18 h. In addition to using a high insulin concentration in the culture medium, a low-melting agarose was also used to embed the disc to prevent it from drifting during the imaging period. This report uses the eye-antennal discs as an example. Photoreceptor R3/4-specific m&#948;0.5-Ga4 expression was followed to demonstrate that photoreceptor differentiation and ommatidial rotation can be observed during a 10 h live imaging period. This is a detailed protocol describing this simple method.

Long-term Live Imaging of Drosophila Eye Disc

This protocol describes a detailed method for the long-term ex vivo culture and live imaging of a Drosophila imaginal disc. It demonstrates photoreceptor differentiation and ommatidial rotation within the 10 h period of live imaging of the eye disc. The protocol is simple and does not require expensive setup.

Live imaging provides the ability to continuously track dynamic cellular and developmental processes in real time. Drosophila larval imaginal discs have ...

A Rapid and Efficient Method to Dissect Pupal Wings of Drosophila Suitable for Immunodetections or PCR Assays

Wing development in Drosophila melanogaster is an ideal model for studying morphogenesis at tissue level. These appendages develop from a group of cells named wing imaginal discs formed during embryonic development. In the larval stages the imaginal discs grow, increasing its number of cells and forming monolayered epithelial&#160;structures. Inside the pupal case, the imaginal discs bud out and fold into bilayers along a line that becomes the future margin of the wing. During this process, the longitudinal primodia veins originate vein cells on the prospective dorsal and ventral surfaces of the wing. During the pupal stage the stripes of vein cells of each surface communicate in order to generate tight tubes; at the same time, the cross-veins begin their formation.
With the help of appropriate molecular markers, it is possible to identify the major elements composing the wing during its development. For this reason, the ability to accurately detect transcripts or proteins in this structure is critical for studying their abundance and localization related to the development process of the wing.
The procedure described here focuses on manipulating pupal wings, providing detailed instructions on how to dissect the wing during the pupal stage. The dissection of pupal tissue is more difficult to perform than their counterparts in third instar larvae. This is why this approach was developed, to obtain rapid and efficient high quality samples. Details of how to immunostain and mount these wing samples, to allow the visualization of proteins or cell components, are provided in the protocol. With little expertise it is possible to collect 8-10 high quality pupal wings in a short amount of time.

A Rapid and Efficient Method to Dissect Pupal Wings of Drosophila Suitable for Immunodetections or PCR Assays

The ability to accurately detect transcripts or proteins in Drosophila tissues is critical for studying their abundance and localization related to the development process. Here is the description of a straightforward procedure to dissect pupal wings. These wings can be used as samples in several techniques (immunohistochemistry, PCR assay, etc.).

Wing development in Drosophila melanogaster is an ideal model for studying morphogenesis at tissue level. These appendages develop from a group of cells ...

Bioengineering of Humanized Bone Marrow Microenvironments in Mouse and Their Visualization by Live Imaging

Human hematopoietic stem cells (HSCs) reside in the bone marrow (BM) niche, an intricate, multifactorial network of components producing cytokines, growth factors, and extracellular matrix. The ability of HSCs to remain quiescent, self-renew or differentiate, and acquire mutations and become malignant depends upon the complex interactions they establish with different stromal components. To observe the crosstalk between human HSCs and the human BM niche in physiological and pathological conditions, we designed a protocol to ectopically model and image a humanized BM niche in immunodeficient mice. We show that the use of different cellular components allows for the formation of humanized structures and the opportunity to sustain long-term human hematopoietic engraftment. Using two-photon microscopy, we can live-image these structures in situ at the single-cell resolution, providing a powerful new tool for the functional characterization of the human BM microenvironment and its role in regulating normal and malignant hematopoiesis.

A method to create and live-image different humanized bone-marrow niches in mice is presented. Based on the supportive niche created by human mesenchymal cells, the addition of human endothelial cells induces the formation of human vessels, while the addition of rhBMP-2 induces the formation of human-mouse chimeric mature bone tissue.

Human hematopoietic stem cells (HSCs) reside in the bone marrow (BM) niche, an intricate, multifactorial network of components producing cytokines, growth ...

Live Imaging of Mouse Secondary Palate Fusion

The fusion of the secondary palatal shelves to form the intact secondary palate is a key process in mammalian development and its disruption can lead to cleft secondary palate, a common congenital anomaly in humans. Secondary palate fusion has been extensively studied leading to several proposed cellular mechanisms that may mediate this process. However, these studies have been mostly performed on fixed embryonic tissues at progressive timepoints during development or in fixed explant cultures analyzed at static timepoints. Static analysis is limited for the analysis of dynamic morphogenetic processes such a palate fusion and what types of dynamic cellular behaviors mediate palatal fusion is incompletely understood. Here we describe a protocol for live imaging of ex vivo secondary palate fusion in mouse embryos. To examine cellular behaviors of palate fusion, epithelial-specific Keratin14-cre was used to label palate epithelial cells in ROSA26-mTmGflox reporter embryos. To visualize filamentous actin, Lifeact-mRFPruby reporter mice were used. Live imaging of secondary palate fusion was performed by dissecting recently-adhered secondary palatal shelves of embryonic day (E) 14.5 stage embryos and culturing in agarose-containing media on a glass bottom dish to enable imaging with an inverted confocal microscope. Using this method, we have detected a variety of novel cellular behaviors during secondary palate fusion. An appreciation of how distinct cell behaviors are coordinated in space and time greatly contributes to our understanding of this dynamic morphogenetic process. This protocol can be applied to mutant mouse lines, or cultures treated with pharmacological inhibitors to further advance understanding of how secondary palate fusion is controlled.

Here, we present a protocol for live imaging of mouse secondary palate fusion using confocal microscopy. This protocol can be used in combination with a variety of fluorescent reporter mouse lines, and with pathway inhibitors for mechanistic insight. This protocol can be adapted for live imaging in other developmental systems.

The fusion of the secondary palatal shelves to form the intact secondary palate is a key process in mammalian development and its disruption can lead to ...

Dissection and Staining of Drosophila Pupal Ovaries

Unlike adult Drosophila ovaries, pupal ovaries are relatively difficult to access and examine due to their small size, translucence, and encasing within a pupal case. The challenge of dissecting pupal ovaries also lies in their physical location within the pupa: the ovaries are surrounded by fat body cells inside the pupal abdomen, and these fat cells must be removed to allow for proper antibody staining. To overcome these challenges, this protocol utilizes customized Pasteur pipets to extract fat body cells from the pupal abdomen. Moreover, a chambered coverglass is used in place of a microcentrifuge tube during the staining process to improve visibility of the pupae. However, despite these and other advantages of the tools used in this protocol, successful execution of these techniques may still involve several days of practice due to the small size of pupal ovaries. The techniques outlined in this protocol could be applied to time course experiments in which ovaries are analyzed at various stages of pupal development.

Dissection and Staining of Drosophila Pupal Ovaries

The Drosophila ovary is an excellent model system for studying stem cell niche development. Though methods for dissecting larval and adult ovaries have been published, pupal ovary dissections require different techniques that have not been published in detail. Here we outline a protocol for dissecting, staining, and mounting pupal ovaries.

Unlike adult Drosophila ovaries, pupal ovaries are relatively difficult to access and examine due to their small size, translucence, and encasing within a ...

Dissection of the Drosophila Pupal Retina for Immunohistochemistry, Western Analysis, and RNA Isolation

The Drosophila pupal retina provides an excellent model system for the study of morphogenetic processes during development. In this paper, we present a reliable protocol for the dissection of the delicate Drosophila pupal retina. Our surgical approach utilizes readily-available microdissection tools to open pupae and precisely extract eye-brain complexes. These can be fixed, subjected to immunohistochemistry, and retinas then mounted onto microscope slides and imaged if the goal is to detect cellular or subcellular structures. Alternatively, unfixed retinas can be isolated from brain tissue, lysed in appropriate buffers and utilized for protein gel electrophoresis or mRNA extraction (to assess protein or gene expression, respectively). Significant practice and patience may be required to master the microdissection protocol described, but once mastered, the protocol enables relatively quick isolation of mainly undamaged retinas.

Dissection of the Drosophila Pupal Retina for Immunohistochemistry, Western Analysis, and RNA Isolation

This paper presents a surgical method for dissecting Drosophila pupal retinas along with protocols for the processing of tissue for immunohistochemistry, western analysis, and RNA-extraction.&#160;

The Drosophila pupal retina provides an excellent model system for the study of morphogenetic processes during development. In this paper, we present a ...

Live Imaging and Analysis of Muscle Contractions in Drosophila Embryo

Coordinated muscle contractions are a form of rhythmic behavior seen early during development in Drosophila embryos. Neuronal sensory feedback circuits are required to control this behavior. Failure to produce the rhythmic pattern of contractions can be indicative of neurological abnormalities. We previously found that defects in protein O-mannosylation, a posttranslational protein modification, affect the axon morphology of sensory neurons and result in abnormal coordinated muscle contractions in embryos. Here, we present a relatively simple method for recording and analyzing the pattern of peristaltic muscle contractions by live imaging of late stage embryos up to the point of hatching, which we used to characterize the muscle contraction phenotype of protein O-mannosyltransferase mutants. Data obtained from these recordings can be used to analyze muscle contraction waves, including frequency, direction of propagation and relative amplitude of muscle contractions at different body segments. We have also examined body posture and taken advantage of a fluorescent marker expressed specifically in muscles to accurately determine the position of the embryo midline. A similar approach can also be utilized to study various other behaviors during development, such as embryo rolling and hatching.

Live Imaging and Analysis of Muscle Contractions in Drosophila Embryo

Here, we present a method to record embryonic muscle contractions in Drosophila embryos in a non-invasive and detail-oriented manner.

Coordinated muscle contractions are a form of rhythmic behavior seen early during development in Drosophila embryos. Neuronal sensory feedback circuits ...

Thawing, Culturing, and Cryopreserving Drosophila Cell Lines

There are currently over 160 distinct Drosophila cell lines distributed by the Drosophila Genomics Resource Center (DGRC). With genome engineering, the number of novel cell lines is expected to increase. The DGRC aims to familiarize researchers with using Drosophila cell lines as an experimental tool to complement and drive their research agenda. Procedures for working with a variety of Drosophila cell lines with distinct characteristics are provided, including protocols for thawing, culturing, and cryopreserving cell lines. Importantly, this publication demonstrates the best practices required to work with Drosophila cell lines to minimize the risk of contaminations from adventitious microorganisms or from other cell lines. Researchers who become familiar with these procedures will be able to delve into the many applications that use Drosophila cultured cells including biochemistry, cell biology and functional genomics.

Thawing, Culturing, and Cryopreserving Drosophila Cell Lines

Drosophila cell lines are important reagents for both fundamental and biomedical research. This article provides protocols for thawing, subculturing, and the cryopreservation of commonly used Drosophila cell lines to assist researchers in incorporating the use of these reagents in their research.

There are currently over 160 distinct Drosophila cell lines distributed by the Drosophila Genomics Resource Center (DGRC). With genome engineering, the ...

Imaging and Analysis of Tissue Orientation and Growth Dynamics in the Developing Drosophila Epithelia During Pupal Stages

Within multicellular organisms, mature tissues and organs display high degrees of order in the spatial arrangements of their constituent cells. A remarkable example is given by sensory epithelia, where cells of the same or distinct identities are brought together via cell-cell adhesion showing highly organized planar patterns. Cells align to one another in the same direction and display equivalent polarity over large distances. This organization of the mature epithelia is established over the course of morphogenesis. To understand how the planar arrangement of the mature epithelia is achieved, it is crucial to track cell orientation and growth dynamics with high spatiotemporal fidelity during development in vivo. Robust analytical tools are also essential to identify and characterize local-to-global transitions. The Drosophila pupa is an ideal system to evaluate oriented cell shape changes underlying epithelial morphogenesis. The pupal developing epithelium constitutes the external surface of the immobile body, allowing long-term imaging of intact animals. The protocol described here is designed to image and analyze cell behaviors at both global and local levels in the pupal abdominal epidermis as it grows. The methodology described can be easily adapted to the imaging of cell behaviors at other developmental stages, tissues, subcellular structures, or model organisms.

Imaging and Analysis of Tissue Orientation and Growth Dynamics in the Developing Drosophila Epithelia During Pupal Stages

This protocol is designed for the imaging and analysis of the dynamics of cell orientation and tissue growth in the Drosophila abdominal epithelia as the fruit fly undergoes metamorphosis. The methodology described here can be applied to the study of different developmental stages, tissues, and subcellular structures in Drosophila or other model organisms.