Focal expression of A-CAM on pillar cells during formation of Corti's tunnel in gerbil cochlea.
BACKGROUND
The organ of Corti in the mammalian cochlea develops from a simple epithelium into a complex structure consisting of as many as ten highly specialized cell types. The purpose of the present study was to examine the possible role of a cell adhesion specific molecule (A-CAM) in mediating morphogenesis of the organ of Corti.


METHODS
The expression of A-CAM was studied in a series of inner ears collected from neonatal gerbils at two days intervals from 0 to twenty days after birth. Immunostaining was performed with a mouse monoclonal antibody raised against A-CAM isolated from chicken cardiac muscle.


RESULTS
The adhesion molecule appeared just prior to opening of the tunnel of Corti and disappeared after full expansion of tunnel space. A-CAM was detected in the basal turn of the cochlea as early as two days after birth and its expression moved progressively toward the apex of the cochlear spiral. It was observed in all three cochlear turns at eight days after birth but disappeared after postnatal day twelve. Immunostaining for A-CAM was localized only to the region where inner and outer pillar cells separate to form the tunnel of Corti.


CONCLUSIONS
A-CAM apparently plays a role in the formation of the tunnel space by modulating apical adhesion above the separation between inner and outer pillar cells.
Nakazawa
K
K
Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston 29425, USA.
Spicer
S S
SS
Schulte
B A
BA
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D000911:Antibodies, Monoclonal; D015820:Cadherins; D015815:Cell Adhesion Molecules / Q000378:metabolism* / Q000502:physiology; D003051:Cochlea / Q000254:growth & development* / Q000378:metabolism; D005849:Gerbillinae; D007150:Immunohistochemistry; D009024:Morphogenesis; D009925:Organ of Corti / Q000254:growth & development* / Q000378:metabolism; D016707:Tissue Fixation / Q000379:methods
D000911:Antibodies, Monoclonal; D015820:Cadherins; C489083:Cdh2 protein, mouse; D015815:Cell Adhesion Molecules