We propose to extend the studies of junctional complexes and cell membranes in the ocular lens of vertebrates. The long-term objectives of this application are to gain a better understanding in structural characteristics, distributions and functional roles of various types of cell junctions in the lens. Cell membranes are the major component of al cell junctions. It is believed that cell junctions and cell membranes play important roles in maintaining normal architecture physiology, and transparency of the lens. We extend our research goals to gain some insights into the roles of cell membranes involved in endocytosis and vesicular transport of useful macromolecules into the lens.
The specific aims of the research plan are as follows: (1) Direct structural analysis and comparison of native gap-junction connexons in lens epithelium and fiber cells, using rapid-freezing techniques; (2) Study association of gap junctions with actin bundles and actin-associated components, using cytochalasin-D treatments, and an improved fixation containing glutaraldehyde, lysine and tannic acid; (3) Immunocytochemical localization of gap junction proteins (MP70 and/or MP26), actin and actin- bundling proteins; (4) Ultrastructural and immunocytochemical analyses of formation of adherens junctions during chick lens morphogenesis; (5) Morphological and immunocytochemical studies of the occurrence, structure and nature of desmosomes and associated cytoskeletal components in lens epithelium of various species; (6) Ultrastructural and immunocytochemical investigations of unique membrane domains (clathrin-like) associated with formation of ball-and-socket junctions in fiber cells; (7) Visualization of structure and distribution of coated vesicles and non-coated vesicles in the lens of various species, using improved fixation and protein tracer methods; (8) Study the effects of growth factors and other factors on fluid-phase and receptor-mediated endocytosis in the lens; (9) Immunocytochemical determination of possible involvements of some growth factors in endocytosis using their specific antibodies as probes. Methodology used incudes (1) transmission electron microscopy using the improved fixation method developed in this laboratory; (2) rapid-freezing in liquid helium temperature without prior chemical fixation, and in conjunction with free-substitution, freeze-fracture and deep-etching techniques; (3) conventional freeze-fracture TEM; (4) immunofluorescence and immunogold labeling techniques, and (5) protein tracer and cytochemical methods.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY005314-10
Application #
3260337
Study Section
Visual Sciences A Study Section (VISA)
Project Start
1983-09-01
Project End
1995-03-31
Budget Start
1992-04-01
Budget End
1993-03-31
Support Year
10
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Morehouse School of Medicine
Department
Type
Schools of Medicine
DUNS #
City
Atlanta
State
GA
Country
United States
Zip Code
30310
Cheng, Catherine; Nowak, Roberta B; Amadeo, Michael B et al. (2018) Tropomyosin 3.5 protects the F-actin networks required for tissue biomechanical properties. J Cell Sci 131:
Hu, Zhengping; Shi, Wen; Riquelme, Manuel A et al. (2017) Connexin 50 Functions as an Adhesive Molecule and Promotes Lens Cell Differentiation. Sci Rep 7:5298
Biswas, Sondip; Son, Alexander; Yu, Qili et al. (2016) Breakdown of interlocking domains may contribute to formation of membranous globules and lens opacity in ephrin-A5(-/-) mice. Exp Eye Res 145:130-139
Cheng, Catherine; Nowak, Roberta B; Biswas, Sondip K et al. (2016) Tropomodulin 1 Regulation of Actin Is Required for the Formation of Large Paddle Protrusions Between Mature Lens Fiber Cells. Invest Ophthalmol Vis Sci 57:4084-99
Cheng, Catherine; Nowak, Roberta B; Gao, Junyuan et al. (2015) Lens ion homeostasis relies on the assembly and/or stability of large connexin 46 gap junction plaques on the broad sides of differentiating fiber cells. Am J Physiol Cell Physiol 308:C835-47
Biswas, Sondip K; Brako, Lawrence; Gu, Sumin et al. (2014) Regional changes of AQP0-dependent square array junction and gap junction associated with cortical cataract formation in the Emory mutant mouse. Exp Eye Res 127:132-42
Biswas, Sondip K; Brako, Lawrence; Lo, Woo-Kuen (2014) Massive formation of square array junctions dramatically alters cell shape but does not cause lens opacity in the cav1-KO mice. Exp Eye Res 125:9-19
Lo, Woo-Kuen; Biswas, Sondip K; Brako, Lawrence et al. (2014) Aquaporin-0 targets interlocking domains to control the integrity and transparency of the eye lens. Invest Ophthalmol Vis Sci 55:1202-12
Zhang, Cheng; Asnaghi, Laura; Gongora, Celine et al. (2011) A developmental defect in astrocytes inhibits programmed regression of the hyaloid vasculature in the mammalian eye. Eur J Cell Biol 90:440-8
Biswas, Sondip K; Lee, Jai Eun; Brako, Lawrence et al. (2010) Gap junctions are selectively associated with interlocking ball-and-sockets but not protrusions in the lens. Mol Vis 16:2328-41

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