The modulation of cell adhesion molecule expression and intercellular junction formation in the developing avian inner ear.
نویسندگان
چکیده
The cells that constitute the membranous labyrinth in the vertebrate inner ear are all derived from a single embryonic source, namely, the otocyst. The mature inner ear epithelia contain different regions with highly differentiated cells, displaying a highly specialized cytoarchitecture. The present study was designed to determine the presence of adherens-type intercellular junctions in this tissue and study the expression of cell adhesion molecules (CAMs) associated with these junctions, namely, A-CAM and L-CAM, in the developing avian inner ear epithelia. The results presented here show that throughout the early otocyst, A-CAM is coexpressed with L-CAM. The formation of asymmetries between sensory and nonsensory areas in the epithelium is accompanied by the modulation of CAMs expression and the assembly of intercellular junctional complexes. A-CAM and L-CAM display reciprocal expression patterns, the former being expressed mostly in the mosaic sensory epithelium, while L-CAM becomes conspicuous in the nonsensory areas but its expression in the sensory region is markedly reduced. Adherens-type junctions and numerous desmosomes are found in the junctional complexes of early otocyst cells. The former persist to maturity of the various inner ear epithelia, whereas desmosomes disappear from junctional complexes of hair cells but remain in the intercellular junctional complexes of all other cell types in the membranous labyrinth. Thus, adherens type intercellular junctions comprise the only defined cytoskeleton-bound junction in mature hair cells. A-CAM-positive cells are also found in the region of the acoustic ganglion in early developmental stages but not in the mature neural elements.
منابع مشابه
A Comparative Study of Serum Level of Vascular Cell Adhesion Molecule-1 (sVCAM-1), Intercellular Adhesion Molecule-1(ICAM-1) and High Sensitive C - reactive protein (hs-CRP) in Normal and Pre-eclamptic Pregnancies
متن کامل
Up-Regulation of Integrinsn α2β1 and α3β1 Expression in Human Foreskin Fibroblast Cells after In-Vitro Infection with Herpes Simplex Virus Type 1
The interaction of Herpes Simplex Virus type 1 (HSV-1) with human fetal foreskin fibroblast (HFFF) cell was studied using a recent isolate of HSV-1 which was propagated in Hep-2 cells. HFFF cells were challenged with HSV-1 with a multiplicity of infection (MOI) of 1 virus/cell for 24 hours. Flow cytometric analysis demonstrated that HSV-1 challenged HFFF cells expressed increased levels of α2β1...
متن کاملاثر یک دوره تمرین هوازی بر شاخصهای عملکرد اندوتلیالی زنان یائسه مبتلا به پرفشار خونی
Background & Aims : Aging and the loss of endogenous estrogen production after menopause are accompanied by increases in blood pressure and endothelial dysfunction. Exercise training improves endothelial function in patients with hypertension. The aim of this study was to examine the effect of aerobic training on some markers of endothelial function in hypertensive postmenopausal women. M...
متن کاملSpatial and temporal distribution of the adherens-junction-associated adhesion molecule A-CAM during avian embryogenesis.
A-CAM (adherens-junction-specific cell adhesion molecule) is a calcium-dependent adhesion molecule which is associated with intercellular adherens junctions in various tissues (Volk & Geiger, 1986, J. Cell Biol. 103, 1441-1450 and 1451-1464). In the present report, we have investigated the distribution of A-CAM during avian morphogenesis by immunofluorescence microscopy and immunoblotting. A-CA...
متن کاملA-CAM: a 135-kD receptor of intercellular adherens junctions. II. Antibody-mediated modulation of junction formation
Intercellular adherens junctions between cultured lens epithelial cells are highly Ca2+-dependent and are readily dissociated upon chelation of extracellular Ca2+ ions. Addition of Ca2+ to EGTA-treated cells results in the recovery of cell-cell junctions including the reorganization of adherens junction-specific cell adhesion molecule (A-CAM), vinculin, and actin (Volk, T., and B. Geiger, 1986,...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Developmental biology
دوره 128 1 شماره
صفحات -
تاریخ انتشار 1988