Studies on corneal endothelial growth and repair 2. increased transcription as detected by incorporation of tritium labeled uridine and tritium labeled actinomycin d
Rothstein, H.; Gordon, S.R.
Tissue and Cell 12(4): 647-660
ISSN/ISBN: 0040-8166 Accession: 006505949
Endothelial cells from injured frog corneas undergo increased 3H-uridine and 3H-actinomycin D (3H-AMD) incorporation as judged by autoradiography. The increase in 3H-AMD binding occurred when living endothelium was labeled in vitro or when fixed preparations were exposed to the drug. The changes in 3H-AMD incorporation detected by the 2 methods were comparable (55 and 62% for living and pre-fixed tissue, respectively). When fixed endothelium was de-histonized with 2N HCl, differential binding of 3H-AMD was eliminated. The enhanced incorporation of 3H-AMD into nuclei was at least partly due to a modification in the association of chromosomal proteins with DNA and not entirely to cell permeability changes that may accompany wound repair. This contrasts with cells killed outright by the injury. These cells bind very large amounts of 3H-AMD compared with their living neighbors. The difference in incorporation was eliminated by prefixation. In the dead cells increased binding may be due to a reduction of cell surface permeability barriers which accompanies cell morbidity.