Open AccessDistinct functions for Netrin-1 in chicken and murine semicircular canal morphogenesis
Author(s) -
Allison Nishitani,
Sho Ohta,
Andrea R. Yung,
Tony del Rio,
Michael I. Gordon,
Victoria E. Abraira,
Evelyn C. Avilés,
Gary C. Schoenwolf,
Donna M. Fekete,
Lisa V. Goodrich
Publication year - 2017
Publication title -
development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.15
H-Index - 36
eISSN - 1477-9129
pISSN - 0950-1991
DOI - 10.1242/dev.144519
Subject(s) - netrin , biology , otic vesicle , morphogenesis , microbiology and biotechnology , inner ear , anatomy , vestibular system , basement membrane , ectopic expression , axon guidance , axon , gene expression , genetics , in situ hybridization , neuroscience , gene
The vestibular system of the inner ear detects head position using three orthogonally oriented semicircular canals; even slight changes in their shape and orientation can cause debilitating behavioral defects. During development, the canals are sculpted from pouches that protrude from the otic vesicle, the embryonic anlage of the inner ear. In the center of each pouch, a fusion plate forms where cells lose their epithelial morphology and the basement membrane breaks down. Cells in the fusing epithelia intercalate and are removed, creating a canal. In mice, fusion depends on the secreted protein Netrin-1, which is necessary for basement membrane breakdown, although the underlying molecular mechanism is unknown. Using gain-of-function approaches, we found that overexpression of Netrin-1 in the chick otic vesicle prevented canal fusion by inhibiting apoptosis. In contrast, ectopic expression of the same chicken Netrin-1 in the mouse otic vesicle, where apoptosis is less prominent, resulted in canal truncation. These findings highlight the importance of apoptosis for tissue morphogenesis and suggest that Netrin-1 may play divergent cellular roles despite its conserved expression during canal morphogenesis in chicken and mouse.