The mammalian lens fiber cell membrane is of great importance in maintaining the integrity of the normal lens. The intrinsic protein component of the lens fiber cell membrane is relatively simple, with four proteins (MP19, MP26, MP46, and MP70) forming the overwhelming majority of the total intrinsic membrane protein. During normal aging and cataractogenesis, changes are observed in the size and biochemical makeup of these four proteins, and they appear to form insoluble aggregates with lens crystallins, resulting in opacities. Little is presently known about the biological function of the above intrinsic membrane proteins, and controversy exists concerning their function in communicating junctions, structural elements of the membrane, or as adhesion proteins. The investigators intend to investigate the function of MP19, MP26, MP46, and MP70 by cloning their coding cDNAs into the baculovirus expression system in order to obtain large quantities of these membrane proteins for further biochemical and functional studies. The isolated proteins will be inserted into artificial unilamellar liposomes and planar bilayers in order to study the ability of each membrane protein to form junctions which will pass molecules of different sizes or exhibit voltage-dependent channels. The recombinant baculovirus will be used to infect cultured Spodoptera frugiperda cells in order to investigate the insertion of recombinant protein into the membrane of the cultured cells, and determine if active junctions are formed. Biochemical, immuno-electron microscopy, and recombinant DNA techniques will be used to carry out the proposed studies.
| Kerscher, S; Church, R L; Boyd, Y et al. (1995) Mapping of four mouse genes encoding eye lens-specific structural, gap junction, and integral membrane proteins: Cryba1 (crystallin beta A3/A1), Crybb2 (crystallin beta B2), Gja8 (MP70), and Lim2 (MP19). Genomics 29:445-50 |
| Church, R L; Wang, J H; Steele, E (1995) The human lens intrinsic membrane protein MP70 (Cx50) gene: clonal analysis and chromosome mapping. Curr Eye Res 14:215-21 |
| Church, R L; Wang, J H (1993) The human lens fiber-cell intrinsic membrane protein MP19 gene: isolation and sequence analysis. Curr Eye Res 12:1057-65 |
