PATTERN OF CELL-DEATH DURING OPTIC CUP FORMATION IN THE TREE SHREW TUPAIA-BELANGERI

Authors
Citation
W. Knabe et Hj. Kuhn, PATTERN OF CELL-DEATH DURING OPTIC CUP FORMATION IN THE TREE SHREW TUPAIA-BELANGERI, Journal of comparative neurology, 401(3), 1998, pp. 352-366
Citations number
47
Categorie Soggetti
Neurosciences,Zoology
ISSN journal
00219967
Volume
401
Issue
3
Year of publication
1998
Pages
352 - 366
Database
ISI
SICI code
0021-9967(1998)401:3<352:POCDOC>2.0.ZU;2-A
Abstract
Developmental cell death during optic cup formation was investigated i n the tree shrew Tupaia belangeri. Twenty-six embryos from days 12 to 16 of prenatal ontogenesis were studied by light microscopy. Prior to the optic vesicle stage, a dorsal area of cell death surrounded the lu men of the V-shaped optic evagination (phase 1). A ventral band of dea d cells, found in the optic vesicle (phase 2), preceded a dorsal focus of cell death (phase 3) previously described as a characteristic avia n feature. During further invagination (phase 4), a peak of cell death was represented by a ventrodorsal band extending from the diencephalo n over the complete optic anlage. The main areas of cell death found i n phases 2 to 4 were, topographically, segments of this band. Also, th e distinct areas of cell death reported in the literature for the vert ebrate species studied so far fit well into this ventrodorsal band fou nd in Tupaia. Thus, most probably, a common spatio-temporal sequence o f cell death exists in all of them. In Tupaia, dead cells concentrated at the diencephalic insertion of the optic stalk, the suboptic necrot ic center (SONC) reported by several authors, were part of the early v entral band of cell death originating from the median floor of the pro sencephalon (phase 2). During optic cup formation, the SONC was part o f the ventrodorsal band and, thus, was not secondarily formed by the s ubdivision of a pre-existing distal ventral area of cell death as repo rted for several other vertebrates. J. Comp. Neurol. 401:352-366, 1998 . (C) 1998 Wiley-Liss, Inc.