In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 98, No. 7 ( 2001-03-27), p. 3873-3878
Abstract:
Within the mammalian inner ear there are six separate sensory
regions that subserve the functions of hearing and balance, although how these sensory regions become specified remains unknown. Each
sensory region is populated by two cell types, the mechanosensory hair cell and the supporting cell, which are arranged in a mosaic in which
each hair cell is surrounded by supporting cells. The proposed mechanism for creating the sensory mosaic is lateral inhibition
mediated by the Notch signaling pathway. However, one of the Notch ligands, Jagged1 ( Jag1 ), does not show an
expression pattern wholly consistent with a role in lateral inhibition, as it marks the sensory patches from very early in their
development—presumably long before cells make their final fate decisions. It has been proposed that Jag1 has a role in
specifying sensory versus nonsensory epithelium within the ear [Adam, J., Myat, A., Roux, I. L., Eddison, M., Henrique, D.,
Ish-Horowicz, D. & Lewis, J. (1998) Development (Cambridge,
U.K.) 125, 4645–4654]. Here we provide experimental evidence that Notch signaling may be involved in specifying sensory regions by
showing that a dominant mouse mutant headturner ( Htu )
contains a missense mutation in the Jag1 gene and
displays missing posterior and sometimes anterior ampullae, structures that house the sensory cristae. Htu /+ mutants also
demonstrate a significant reduction in the numbers of outer hair cells in the organ of Corti. Because lateral inhibition mediated by Notch
predicts that disruptions in this pathway would lead to an increase in hair cells, we believe these data indicate an earlier role for Notch
within the inner ear.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.071496998
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
2001
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
