The processes governing differential protein expression in preimplantation lineages were investigated using a monoclonal antibody recognising the tight junction polypeptide, ZO-1. ZO-1 localises to the maturing tight junction membrane domain in the polarised trophectoderm lineage from compaction (8-cell stage) onwards, ultimately forming a zonular belt around each trophectoderm cell of the blas...

Epithelial differentiation including tight junction (TJ) formation occurs exclusively within the trophectoderm (TE) lineage of the mouse blastocyst. Here we examine mechanisms by which TJ protein membrane assembly might be regulated by protein kinase C (PKC) in the embryo. To overcome the inherent staging asynchrony of individual blastomeres within intact embryos, we have used isolated inner ce...

The regulation of transendothelial fluid flow by glucocorticoids was studied in vitro with use of human endothelial cells cultured from Schlemm's canal (SCE) and the trabecular meshwork (TM) in conjunction with computer-linked flowmeters. After 2-7 wk of 500 nM dexamethasone (Dex) treatment, the following physiological, morphometric, and biochemical alterations were observed: a 3- to 5-fold inc...

OBJECTIVE Tight junctions are multicomponent structures, with claudin proteins defining paracellular permeability. Claudin 3 is a candidate for the exceptional "tightness" of human urothelium, being localised to the terminal tight junction (TJ) of superficial cells. Our aim was to determine whether claudin 3 plays an instigating and/or a functional role in the urothelial TJ. MATERIALS AND MET...

Zonula occludens (ZO)-1 is a multi-domain scaffold protein known to have critical roles in the establishment of cell-cell adhesions and the maintenance of stable tissue structures through the targeting, anchoring, and clustering of transmembrane adhesion molecules and cytoskeletal proteins. Here, we report that ZO-1 directly binds to MRCKβ, a Cdc42 effector kinase that modulates cell protrusion...

AIMS Remodelling of gap junctions, involving reduction of total gap junction quantity and down-regulation of connexin43 (Cx43), contributes to the arrhythmic substrate in congestive heart failure. However, little is known of the underlying mechanisms. Recent studies from in vitro systems suggest that the connexin-interacting protein zonula occludens-1 (ZO-1) is a potential mediator of gap junct...

The tight junction is an intricate seal between adjoining epithelial cells that also separates the apical and basolateral membranes within these cells. A paper in this issue of Cell by Umeda et al. (2006) demonstrates that loss of the ZO scaffolding proteins prevents the formation of tight junctions but surprisingly does not perturb apico-basal polarity.

A method is given for proving uniqueness theorems for some inverse problems. The method is based on a result on completeness of the products of solutions to PDE. As an example, the following uniqueness theorems are proved: (1) the scattering amplitude A(fY, 0, k) known for all W, BE Sz and a fixed k > 0 determines the compactly supported q(x)~ L*(D) uniquely; (2) the surface data u(x,y, k) know...