Mark Berryman, Ph.D.
Associate Professor of Cell Biology
Department of Biomedical Sciences
237 Life Sciences

Research Photo Gallery:
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  Figure 1: Classic microvilli of the brush border that lines the luminal surface of absorptive epithelial cells. This image is from neonatal rat intestine. Note the orderly arrangement and uniform shape and size of the microvilli. Bundles of parallel actin filaments within each microvillus project downward into the apical cytoplasm of the cell.

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  Figure 2: Microvilli are not all created equal. Unlike the intestinal brush border, microvilli lining the apical surface of human placental syncytiotrophoblast epithelium are variable in distribution and shape. Presumably, these microvilli are less rigid and more dynamic than microvilli of the intestinal brush border, perhaps reflecting active endocytosis and membrane trafficking in these cells. Placental microvilli contain high levels of ezrin, a member of the ERM (Ezrin/Radixin/Moesin) family of membrane-cytoskeletal crosslinking proteins.

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  Figure 3: Cryosection of intact human placenta tissue stained for ezrin (green) and F-actin (red). The syncytiotrophoblast epithelium is yellow due to intense staining and colocalization of ezrin and actin in surface microvilli.

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  Figure 4: Immunoelectron micrograph in which 10-nm gold particles reveal the localization of ezrin to microvilli in human placenta. In many cases, gold particles are located on or near the plasma membrane.

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  Figure 5: Microvilli isolated from human placenta. CLIC5A (Chloride Intracellular Channel 5A) was biochemically isolated from this type of preparation by virtue of its interaction with ezrin and other actin-associated proteins.

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  Figure 6: Cultured human JEG-3 choriocarcinoma cells stained for ezrin (green), CLIC5A (red), and DNA (blue). The surface microvilli appear yellow due to the colocalization of ezrin and CLIC5A.

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  Figure 7: Comparison of percent amino acid sequence identity and number of amino acid residues for members of the human CLIC (Chloride Intracellular Channel) protein family, which is comprised of six distinct genes. Gene mutations that cause deficiencies of CLIC5A can result in deafness and vertigo in humans and mice.

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  Figure 8: Hearing takes place in the organ of Corti, the sensorineural organ of the cochlea. It consists of mechanosensory hair cells, nerve fibers, and supporting structures. This scanning electron micrograph shows the hair bundles that project from the top surface of each hair cell. Each hair bundle consists of a highly organized group of stereocilia (“giant microvilli”), pencil-shaped protrusions containing a tightly packed bundle of parallel actin filaments. There is one row of inner hair cells and three rows of outer hair cells. Each hair cell is surrounded by support cells with smaller, more typical microvilli, resembling “shag carpet”. Credit: Leonardo Andrade (collaborator)

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  Figure 9: Localization of CLIC5A (green) and actin (red) in the organ of Corti from guinea pig inner ear. CLIC5A is concentrated in hair bundles that project from the apical surface of hair cells, which function as mechanosensory organelles in the auditory and vestibular systems. CLIC5A staining is prominent in the single row of inner hair cells towards the bottom of the field, and all three rows of outer hair cells in the upper part of the field. The red staining is primarily associated with the support cells of the neurosensory epithelium.

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  Figure 10: Confocal image of CLIC5A (green) and β-actin (red) in inner (bottom half) and outer (upper half) hair cells from adult mouse. The key point here is that CLIC5 concentrates at the base of stereocilia, which is a distinct compartment with special structural and functional significance. Credit: Felipe Salles (collaborator)

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  Figure 11: High magnification immunoelectron micrograph of CLIC5A stained with 10-nm gold particles. This ultrathin section grazes through parts of several stereocilia. Gold particles are more plentiful near the base of stereocilia (bottom of field), and are located near the plasma membrane between stereocilia. Credit: Felipe Salles (collaborator)

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  Figure 12: Confocal image of Radixin (red) and F-actin (green) in inner (bottom half) and outer (upper half) hair cells from adult rat. Radixin, another deafness-associated protein, concentrates at the base of stereocilia.

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  Figure 13: Confocal overview of apical turn of neonatal mouse cochlea stained for phosphorylated Radixin (green) and β-actin (red): superimposed on DIC image (gray). The phosphorylated form of Radixin corresponds to its functionally active conformation as a membrane-cytoskeletal crosslinker. Credit: Soichi Tanda (collaborator)

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  Figure 14: Colocalization of CLIC4 (green) and γ-tubulin (red) in a pair of centrosomes of a cultured human JEG-3 choriocarcinoma cell in metaphase: DNA (blue). The centrosomes appear yellow due to the strong overlap in staining of CLIC4 and γ-tubulin. This image shows that in addition to actin-based organelles, such as microvilli, CLIC proteins can also associate with microtubule-based cytoskeletal structures.

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  Figure 15: Localization of CLIC1 (green) to poles of a metaphase mitotic spindle (α-tubulin, red) in a cultured NIH 3T3 fibroblast.

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  Figure 16: Localization of CLIC4 (green) to the center of a microtubule aster (red) in a cultured human JEG-3 choriocarcinoma cell in interphase: DNA (blue).

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  Figure 17: Cytokinesis in cultured human JEG-3 choriocarcinoma cells stained with CLIC4 (green) and α-tubulin (red): DNA (blue). CLIC4 is highly concentrated at the midbody, the site of abscission that separates two daughter cells during the final stages of mitosis.

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  Figure 18: Localization of CLIC4 (red) to kinetochores identified by human CREST autoantibody (green) during metaphase in a cultured bovine aortic endothelial cells: DNA (blue). Kinetochores consist of a large protein complex associated with the centromere of a chromosome during cell division, to which the mictotubules of the mitotic spindle attach.

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  Figure 19: Localization of CLIC4 to kinetochores of bovine aortic endothelial cells in different stages of mitosis. Discrete dots of CLIC4 first appear during prophase after centrosome duplication and initiation of chromosome condensation. In metaphase, the CLIC4 dots align parallel to the long axis of the mitotic spindle (arrows) and overlap with the condensed chromosomes on the metaphase plate. In telophase, the CLIC4 dots are clustered at opposite poles of the spindle apparatus (arrowheads).

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  Figure 20: Synchronous cell division in a syncytial blastoderm of a developing fruit fly (Drosophila melanogaster) embryo. After fertilization, the embryo undergoes an amazing series of 13 metasynchronous mitotic divisions to produce nearly 6,000 nuclei in a matter of a couple of hours. The embryo was stained with antibody against β-tubulin (red) to label mitotic spindles and DAPI (blue) to label DNA.

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  Figure 21: Localization of CLIC (green), β-tubulin (red) and DNA (blue) in developing head of a stage 10 Drosophila embryo: this is a lateral view with anterior end up, and ventral at side left. CLIC is highly concentrated in the apical region of columnar epithelial cells of the stomodeum (arrow), which will form the foregut. In addition, the cell borders (actin-rich cortex) are outlined by intense CLIC staining, specifically in metaphase cells located in mitotic zone 3 (top left), as well as in mitotic zones 5 and 9, near the cephalic furrow (middle). Mitotic zones represent discrete building blocks for various functional units of the larva, ultimately serving as a blueprint for the body plan of the adult fly.

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  Figure 22: Lateral view of stage 11 Drosophila embryo stained for CLIC (green), β-tubulin (red) and DNA (blue): anterior is left and ventral is bottom. In addition to prominent CLIC staining at the plasma membrane of mitotic cells (look for the large red dots, which are centrosomes), CLIC is enriched in cells along the ventral midline as well as the epithelial cells of the developing tracheal placodes (asterisks). These placodes will invaginate as nascent tubes, grow in length, fuse together, and branch into an interconnected network of about 10,000 air-filled tubes that allow for gas transport. This “tree” of interconnected branching tubes is analogous to the human lung.

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  Figure 23: Dorsal closure: this is the final major morphogenetic event in Drosophila embryogenesis. This is a view looking down on the “back” of an embryo stained for β-tubulin (green) and actin filaments (red), the two major cytoskeletal filaments in Drosophila. The actin filaments form two giant symmetrical cables, which resemble the eye of a needle. These cables stitch together two opposite sides of the epithelium (“skin”) to fill the red gap (underlying amnioserosa tissue layer) in a manner a cut in the skin heals. Defects in this process during human embryonic development represent a type of birth defect that involves malformation of the spinal cord.

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  Figure 24: Localization of CLIC (green) and β-tubulin (red) at different stages of dorsal closure: merged images of CLIC and β-tubulin appear yellow in the right column. Dorsal view (anterior/head, left) for all embryos. Top, middle, and bottom rows show high concentration of CLIC (arrows) at sites of progressive zippering of opposing epithelial sheets. This process is analogous to pulling on strings of a purse, where the strings are the actin cables and the purse bag is the epithelium. Note that CLIC is enriched, just before and after, the epithelium stitches together.

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  Figure 25: Pair of third larval instar salivary glands expressing Lifeact-GFP to visualize actin filaments (green), and labeled with phalloidin (red), a separate marker for actin filaments. At the end of larval development, these glands secrete a sticky “glue” that is expectorated to provide a substrate for subsequent pupal development. The bulk of the tissue shown is the glandular component: at the top of the image is pair of faint, red-stained ducts that deliver secretory product into a common duct that empties into the mouth. Credit: Soichi Tanda (collaborator)

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  Figure 26: Scanning electron micrograph of an adult fly head. Prominent features are the eyes, the antenna, which detects odors and motion, and the proboscis, an snout-like tubular appendage used for feeding and sucking. The compound eye consists of approximately 800 ommatidial units and mechanosensory bristles. Each ommatidium contains a set of photoreceptor cells and associated support cells, including cone cells and pigment cells.

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  Figure 27: Lateral view of differentiating photoreceptors in pupal eye stained for CLIC (green), armadillo (red), and DNA (blue). Light would enter the tissue from the top of the image: the photoreceptor cells are very tall, and form a channel to capture the light. The bright green staining at the top of the image reflects high levels of CLIC in the microvilli of cone cells: these cells form the cornea, which acts as a lens. The thin strands of red and green running top-to-bottom reveal the localization of CLIC to the rhabdomeres, extraordinary specializations of the photoreceptor apical surface that that contain a tightly packed array of approximately 60,000 microvilli, serving to enhance capacity for detection of light.

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  Figure 28: Drosophila blood cell stained for actin filaments (red), acetylated α-tubulin (green), and DNA (blue). This type of blood cell, a lamellocyte, is part of the insect immune system. It is a relatively large cell: the nucleus is located in the center, and a complex network of overlapping actin filaments and microtubules gives a yellowish-green appearance to the cells’ cytoskeleton. In addition to their close association with actin filaments, the microtubules often show conspicuous associations with the plasma membrane of the cell.

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Last updated: 09/05/2017