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The p57 Kip2 cyclin kinase inhibitor is expressed by a restricted set of amacrine cells in the rodent retina
Author(s) -
Dyer Michael A.,
Cepko Constance L.
Publication year - 2000
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/1096-9861(20010122)429:4<601::aid-cne7>3.0.co;2-v
Subject(s) - amacrine cell , biology , retina , inner nuclear layer , calbindin , calretinin , ganglion cell layer , microbiology and biotechnology , inner plexiform layer , population , neuroscience , choline acetyltransferase , neurotransmitter , cholinergic , central nervous system , immunology , immunohistochemistry , demography , sociology
Amacrine cells in the vertebrate retina can be grouped according to morphology into distinct types, which are organized into characteristic mosaics. Each type is believed to perform a unique role in visual signal processing. Neurotransmitters and calcium binding proteins have served as important markers for amacrine cell populations, yet many types remain to be characterized at the molecular level. We have found that a cyclin kinase inhibitor, p57 Kip2 , is expressed in a restricted group of amacrine cells in the inner nuclear layer (INL) and ganglion cell layer (GCL) of the rodent retina. Whole‐mount antibody staining revealed that the p57 Kip2 amacrine cells are evenly distributed across the retina with a density of 1654 ± 63 cells/mm 2 in the INL and 994 ± 26 cells/mm 2 in the GCL. These amacrine cells accumulate the major inhibitory neurotransmitter γ‐aminobutyric acid (GABA) but do not accumulate high levels of glycine. In addition, p57 Kip2 immunoreactivity does not colocalize with any of the previously identified amacrine cell markers including calbindin, calretinin, parvalbumin, choline acetyltransferase, and tyrosine hydroxylase. To determine whether the p57 Kip2 population of amacrine cells is organized into a regular or a random mosaic, nearest neighbor analysis was performed for both the INL and GCL populations. Results from this analysis demonstrated that the p57 Kip2 ‐immunoreactive amacrine cells are randomly organized and therefore they are likely to constitute two or more distinct populations. This new molecular marker will serve as a useful tool for future studies on the development and function of amacrine cells in the vertebrate retina. J. Comp. Neurol. 429:601–614, 2001. © 2000 Wiley‐Liss, Inc.